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Donkey milk consumption exerts anti-inflammatory properties by normalizing antimicrobial peptides levels in Paneth's cells in a model of ileitis in mice. Eur J Nutr 2016; 57:155-166. [PMID: 27581119 DOI: 10.1007/s00394-016-1304-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 08/23/2016] [Indexed: 12/18/2022]
Abstract
PURPOSE In this study, we showed the beneficial effects of donkey milk (DM) on inflammatory damages, endogenous antimicrobial peptides levels and fecal microbiota profile in a mice model of Crohn's disease. Nowadays, new strategies of microbiome manipulations are on the light involving specific diets to induce and/or to maintain clinical remission. Interest of DM is explained by its high levels of antimicrobial peptides which confer it anti-inflammatory properties. METHODS C57BL/6 mice were orally administered with or without indomethacin for 5 days and co-treated with vehicle, DM or heated DM during 7 days. Intestinal length and macroscopic damage scores (MDSs) were determined; ileal samples were taken off for microscopic damage (MD), lysozyme immunostaining and mRNA α-defensin assessments. Ileal luminal content and fecal pellets were collected for lysozyme enzymatic activity and lipocalin-2 (LCN-2) evaluations. Fecal microbiota profiles were compared using a real-time quantitative PCR-based analysis. RESULTS Administration of indomethacin caused an ileitis in mice characterized by (1) a decrease in body weight and intestinal length, (2) a significant increase in MDS, MD and LCN-2, (3) a reduction in both α-defensin mRNA expression and lysozyme levels in Paneth's cells reflected by a decrease in lysozyme activity in feces, and (4) a global change in relative abundance of targeted microbial communities. DM treatment significantly reduced almost of all these ileitis damages, whereas heated DM has no impact on ileitis. CONCLUSIONS DM consumption exerts anti-inflammatory properties in mice by restoring the endogenous levels of antimicrobial peptides which contribute in turn to reduce microbiota imbalance.
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Fouhse J, Zijlstra R, Willing B. The role of gut microbiota in the health and disease of pigs. Anim Front 2016. [DOI: 10.2527/af.2016-0031] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- J.M. Fouhse
- Department of Agriculture, Food, and Nutritional Science, University of Alberta, Edmonton AB T6G 2P5, Canada
| | - R.T. Zijlstra
- Department of Agriculture, Food, and Nutritional Science, University of Alberta, Edmonton AB T6G 2P5, Canada
| | - B.P. Willing
- Department of Agriculture, Food, and Nutritional Science, University of Alberta, Edmonton AB T6G 2P5, Canada
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Burcelin R. Gut microbiota and immune crosstalk in metabolic disease. Mol Metab 2016; 5:771-81. [PMID: 27617200 PMCID: PMC5004167 DOI: 10.1016/j.molmet.2016.05.016] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 05/24/2016] [Accepted: 05/31/2016] [Indexed: 12/29/2022] Open
Abstract
Background Gut microbiota is considered as a major regulator of metabolic disease. This reconciles the notion of metabolic inflammation and the epidemic development of the disease. In addition to evidence showing that a specific gut microbiota characterizes patients with obesity, type 2 diabetes, and hepatic steatosis, the mechanisms causal to the disease could be related to the translocation of microbiota from the gut to the tissues, inducing inflammation. The mechanisms regulating such a process are based on the crosstalk between the gut microbiota and the host immune system. The hologenome theory of evolution supports this concept and implies that therapeutic strategies aiming to control glycemia should take into account both the gut microbiota and the host immune system. Scope of review This review discusses the latest evidence regarding the bidirectional impact of the gut microbiota on host immune system crosstalk for the control of metabolic disease, hyperglycemia, and obesity. To avoid redundancies with the literature, we will focus our attention on the intestinal immune system, identifying evidence for the generation of novel therapeutic strategies, which could be based on the control of the translocation of gut bacteria to tissues. Such novel strategies should hamper the role played by gut microbiota dysbiosis on the development of metabolic inflammation. Major conclusions Recent evidence in rodents allows us to conclude that an impaired intestinal immune system characterizes and could be causal in the development of metabolic disease. The fine understanding of the molecular mechanisms should allow for the development of a first line of treatment for metabolic disease and its co-morbidities. This article is part of a special issue on microbiota.
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Affiliation(s)
- Rémy Burcelin
- Institut National de la Santé et de la Recherche Médicale (INSERM), Toulouse, France
- Université Paul Sabatier (UPS), Unité Mixte de Recherche (UMR) 1048, Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), F-31432 Toulouse Cedex 4, France
- Inserm 1048, Hôpital Rangueil, 31400 Toulouse, France. Tel.: +33 561 32 56 14; fax: +33 561 32 56 21.Inserm 1048Hôpital RangueilToulouse31400France
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The Impact of Lactobacillus casei on the Composition of the Cecal Microbiota and Innate Immune System Is Strain Specific. PLoS One 2016; 11:e0156374. [PMID: 27244133 PMCID: PMC4887021 DOI: 10.1371/journal.pone.0156374] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 05/13/2016] [Indexed: 02/07/2023] Open
Abstract
The probiotic function to impact human health is thought to be related to their ability to alter the composition of the gut microbiota and modulate the human innate immune system. The ability to function as a probiotic is believed to be strain specific. Strains of Lactobacillus casei are commonly utilized as probiotics that when consumed alter the composition of the gut microbiota and modulate the host immune response. L. casei strains are known to differ significantly in gene content. The objective of this study was to investigate seven different L. casei strains for their ability to alter the murine gut microbiota and modulate the murine immune system. C57BL/6 mice were fed L. casei strains at a dose of 108 CFU/day/mouse for seven days and sacrificed 3.5h after the last administration. The cecal content and the ileum tissue were collected for microbiota analysis and immune profiling, respectively. While 5 of the L. casei strains altered the gut microbiota in a strain specific manner, two of the strains did not alter the overall cecal microbiota composition. The observed changes cluster into three groups containing between 1 and 2 strains. Two strains that did not affect the gut microbiota composition cluster together with the control in their impact on pattern recognition receptors (PRRs) expression, suggesting that the ability to alter the cecal microbiota correlates with the ability to alter PRR expression. They also cluster together in their impact on the expression of intestinal antimicrobial peptides (AMPs). This result suggests that a relationship exists between the capability of a L. casei strains to alter the composition of the gut microbiota, PRR regulation, and AMP regulation.
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Abstract
The large number of intestinal microorganisms, which exceeds the total number of human cells by ten folds, alludes to a significant contribution to human health. This is vivid in enteric and some systemic diseases emanating from disruption of the microbiota. As life style keeps shifting towards disruption of the microbiota in most societies worldwide, interest in the contribution of the microbiota to gut health has grown enormously. Many studies have been conducted to elucidate the exact contribution of the microbiota to human health. The knowledge gained from these studies indicates that the microbiota interacts with the intestinal milieu to maintain gut health. In this review, the crosstalk of microbiota with the intestinal physicochemical barrier pivotal to the gut innate immunity is highlighted. In particular, the review focuses on the role of the microbiota on competitive exclusion of pathogens, intestinal pH, epithelial mechanical barrier integrity, apical actin cytoskeleton, antimicrobial peptides, and the mucus layer. Understanding this microbe-host relationship will provide useful insight into overcoming some diseases related to the disruption of the host microbiota.
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Affiliation(s)
- J J Malago
- Department of Veterinary Pathology, Faculty of Veterinary Medicine, Sokoine University of Agriculture, P.O. Box 3203, Chuo Kikuu, Morogoro, Tanzania
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Aktas B, De Wolfe TJ, Tandee K, Safdar N, Darien BJ, Steele JL. The Effect of Lactobacillus casei 32G on the Mouse Cecum Microbiota and Innate Immune Response Is Dose and Time Dependent. PLoS One 2015; 10:e0145784. [PMID: 26714177 PMCID: PMC4705108 DOI: 10.1371/journal.pone.0145784] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 12/08/2015] [Indexed: 01/12/2023] Open
Abstract
Lactobacilli have been associated with a variety of immunomodulatory effects and some of these effects have been related to changes in gastrointestinal microbiota. However, the relationship between probiotic dose, time since probiotic consumption, changes in the microbiota, and immune system requires further investigation. The objective of this study was to determine if the effect of Lactobacillus casei 32G on the murine gastrointestinal microbiota and immune function are dose and time dependent. Mice were fed L. casei 32G at doses of 106, 107, or 108 CFU/day/mouse for seven days and were sacrificed 0.5h, 3.5h, 12h, or 24h after the last administration. The ileum tissue and the cecal content were collected for immune profiling by qPCR and microbiota analysis, respectively. The time required for L. casei 32G to reach the cecum was monitored by qPCR and the 32G bolus reaches the cecum 3.5h after the last administration. L. casei 32G altered the cecal microbiota with the predominance of Lachnospiraceae IS, and Oscillospira decreasing significantly (p < 0.05) in the mice receiving 108 CFU/mouse 32G relative to the control mice, while a significant (p < 0.05) increase was observed in the prevalence of lactobacilli. The lactobacilli that increased were determined to be a commensal lactobacilli. Interestingly, no significant difference in the overall microbiota composition, regardless of 32G doses, was observed at the 12h time point. A likely explanation for this observation is the level of feed derived-nutrients resulting from the 12h light/dark cycle. 32G results in consistent increases in Clec2h expression and reductions in TLR-2, alpha-defensins, and lysozyme. Changes in expression of these components of the innate immune system are one possible explanation for the observed changes in the cecal microbiota. Additionally, 32G administration was observed to alter the expression of cytokines (IL-10rb and TNF-α) in a manner consistent with an anti-inflammatory response.
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Affiliation(s)
- Busra Aktas
- Department of Food Science, University of Wisconsin, Madison, WI, United States of America
| | - Travis J. De Wolfe
- Department of Food Science, University of Wisconsin, Madison, WI, United States of America
| | - Kanokwan Tandee
- Food Science and Technology, Maejo University, Chiangmai, Thailand
| | - Nasia Safdar
- Infectious Diseases Division, Department of Medicine, University of Wisconsin, Madison, WI, United States of America
- William S. Middleton Veterans Affairs Hospital, Madison, WI, United States of America
| | - Benjamin J. Darien
- Animal Health and Biomedical Sciences, University of Wisconsin, Madison, WI, United States of America
| | - James L. Steele
- Department of Food Science, University of Wisconsin, Madison, WI, United States of America
- * E-mail:
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57
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Kisseleva EP. Innate immunity underlies symbiotic relationships. BIOCHEMISTRY (MOSCOW) 2015; 79:1273-85. [PMID: 25716721 DOI: 10.1134/s0006297914120013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Here, the modern data regarding interactions between normal microbiota and barrier tissues in plants, humans and animals are reviewed. The main homeostatic mechanisms responsible for interactions between epithelium and innate immune cells with symbiotic bacteria are described. A key step in this process is recognition of soluble microbial products by ligation to pattern-recognition receptors expressed on the host cells. As a result, epithelial cells secrete mucus, antibacterial peptides and immunoregulatory molecules. The main outcomes from immunological reactions towards symbiotic bacteria involve development of conditions for formation and maintenance of microbial biocenosis as well as providing safety for the host. Also, it is considered important to preserve and transfer beneficial bacteria to progeny.
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Affiliation(s)
- E P Kisseleva
- Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, 197376, Russia.
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58
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Laukens D, Brinkman BM, Raes J, De Vos M, Vandenabeele P. Heterogeneity of the gut microbiome in mice: guidelines for optimizing experimental design. FEMS Microbiol Rev 2015; 40:117-32. [PMID: 26323480 PMCID: PMC4703068 DOI: 10.1093/femsre/fuv036] [Citation(s) in RCA: 250] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2015] [Indexed: 02/07/2023] Open
Abstract
Targeted manipulation of the gut flora is increasingly being recognized as a means to improve human health. Yet, the temporal dynamics and intra- and interindividual heterogeneity of the microbiome represent experimental limitations, especially in human cross-sectional studies. Therefore, rodent models represent an invaluable tool to study the host–microbiota interface. Progress in technical and computational tools to investigate the composition and function of the microbiome has opened a new era of research and we gradually begin to understand the parameters that influence variation of host-associated microbial communities. To isolate true effects from confounding factors, it is essential to include such parameters in model intervention studies. Also, explicit journal instructions to include essential information on animal experiments are mandatory. The purpose of this review is to summarize the factors that influence microbiota composition in mice and to provide guidelines to improve the reproducibility of animal experiments. Given the unmet need for standardizing the experimental work flow related to gut microbial research in animals, guidelines are required to isolate true effects from confounding factors.
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Affiliation(s)
- Debby Laukens
- Department of Gastroenterology, Ghent University, B-9000 Ghent, Belgium
| | - Brigitta M Brinkman
- Inflammation Research Center, VIB, B-9052 Ghent, Belgium Department of Biomedical Molecular Biology, Ghent University, B-9052 Ghent, Belgium
| | - Jeroen Raes
- Center for the Biology of Disease, VIB, B-3000 Leuven, Belgium Department Microbiology and Immunology, KU Leuven, B-3000 Leuven, Belgium
| | - Martine De Vos
- Department of Gastroenterology, Ghent University, B-9000 Ghent, Belgium
| | - Peter Vandenabeele
- Inflammation Research Center, VIB, B-9052 Ghent, Belgium Department of Biomedical Molecular Biology, Ghent University, B-9052 Ghent, Belgium Methusalem Program, Ghent University, B-9000 Ghent, Belgium
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59
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How the Intricate Interaction among Toll-Like Receptors, Microbiota, and Intestinal Immunity Can Influence Gastrointestinal Pathology. J Immunol Res 2015; 2015:489821. [PMID: 26090491 PMCID: PMC4452102 DOI: 10.1155/2015/489821] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 10/01/2014] [Accepted: 10/27/2014] [Indexed: 12/12/2022] Open
Abstract
The gut is able to maintain tolerance to microbial and food antigens. The intestine minimizes the number of harmful bacteria by shaping the microbiota through a symbiotic relationship. In healthy human intestine, a constant homeostasis is maintained by the perfect regulation of microbial load and the immune response generated against it. Failure of this balance may result in various pathological conditions. Innate immune sensors, such as Toll-like receptors (TLRs), may be considered an interface among intestinal epithelial barrier, microbiota, and immune system. TLRs pathway, activated by pathogens, is involved in the pathogenesis of several infectious and inflammatory diseases. The alteration of the homeostasis between physiologic and pathogenic bacteria of intestinal flora causes a condition called dysbiosis. The breakdown of homeostasis by dysbiosis may increase susceptibility to inflammatory bowel diseases. It is evident that environment, genetics, and host immunity form a highly interactive regulatory triad that controls TLR function. Imbalanced relationships within this triad may promote aberrant TLR signaling, critically contributing to acute and chronic intestinal inflammatory processes, such as in IBD, colitis, and colorectal cancer. The study of interactions between different components of the immune systems and intestinal microbiota will open new horizons in the knowledge of gut inflammation.
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60
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Rakoff-Nahoum S, Kong Y, Kleinstein SH, Subramanian S, Ahern PP, Gordon JI, Medzhitov R. Analysis of gene-environment interactions in postnatal development of the mammalian intestine. Proc Natl Acad Sci U S A 2015; 112:1929-36. [PMID: 25691701 PMCID: PMC4343130 DOI: 10.1073/pnas.1424886112] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Unlike mammalian embryogenesis, which takes place in the relatively predictable and stable environment of the uterus, postnatal development can be affected by a multitude of highly variable environmental factors, including diet, exposure to noxious substances, and microorganisms. Microbial colonization of the intestine is thought to play a particularly important role in postnatal development of the gastrointestinal, metabolic, and immune systems. Major changes in environmental exposure occur right after birth, upon weaning, and during pubertal maturation into adulthood. These transitions include dramatic changes in intestinal contents and require appropriate adaptations to meet changes in functional demands. Here, we attempt to both characterize and provide mechanistic insights into postnatal intestinal ontogeny. We investigated changes in global intestinal gene expression through postnatal developmental transitions. We report profound alterations in small and large intestinal transcriptional programs that accompany both weaning and puberty in WT mice. Using myeloid differentiation factor 88 (MyD88)/TIR-domain-containing adapter-inducing interferon-β (TRIF) double knockout littermates, we define the role of toll-like receptors (TLRs) and interleukin (IL)-1 receptor family member signaling in postnatal gene expression programs and select ontogeny-specific phenotypes, such as vascular and smooth muscle development and neonatal epithelial and mast cell homeostasis. Metaanalysis of the effect of the microbiota on intestinal gene expression allowed for mechanistic classification of developmentally regulated genes by TLR/IL-1R (TIR) signaling and/or indigenous microbes. We find that practically every aspect of intestinal physiology is affected by postnatal transitions. Developmental timing, microbial colonization, and TIR signaling seem to play distinct and specific roles in regulation of gene-expression programs throughout postnatal development.
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Affiliation(s)
- Seth Rakoff-Nahoum
- Howard Hughes Medical Institute, Department of Immunobiology, Division of Infectious Diseases, Department of Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115
| | - Yong Kong
- Department of Molecular Biophysics and Biochemistry, W. M. Keck Foundation Biotechnology Resource Laboratory, and
| | - Steven H Kleinstein
- Interdepartmental Program in Computational Biology and Bioinformatics and Department of Pathology, Yale University School of Medicine, New Haven, CT 06510
| | - Sathish Subramanian
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63108; and
| | - Philip P Ahern
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63108; and
| | - Jeffrey I Gordon
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63108; and
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New role for human α-defensin 5 in the fight against hypervirulent Clostridium difficile strains. Infect Immun 2014; 83:986-95. [PMID: 25547793 DOI: 10.1128/iai.02955-14] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Clostridium difficile infection (CDI), one of the most common hospital-acquired infections, is increasing in incidence and severity with the emergence and diffusion of hypervirulent strains. CDI is precipitated by antibiotic treatment that destroys the equilibrium of the gut microbiota. Human α-defensin 5 (HD5), the most abundant enteric antimicrobial peptide, is a key regulator of gut microbiota homeostasis, yet it is still unknown if C. difficile, which successfully evades killing by other host microbicidal peptides, is susceptible to HD5. We evaluated, by means of viability assay, fluorescence-activated cell sorter (FACS) analysis, and electron microscopy, the antimicrobial activities of α-defensins 1 and 5 against a panel of C. difficile strains encompassing the most prevalent epidemic and hypervirulent PCR ribotypes in Europe (012, 014/020, 106, 018, 027, and 078). Here we show that (i) concentrations of HD5 within the intestinal physiological range produced massive C. difficile cell killing; (ii) HD5 bactericidal activity was mediated by membrane depolarization and bacterial fragmentation with a pattern of damage peculiar to C. difficile bacilli, compared to commensals like Escherichia coli and Enterococcus faecalis; and (iii) unexpectedly, hypervirulent ribotypes were among the most susceptible to both defensins. These results support the notion that HD5, naturally present at very high concentrations in the mucosa of the small intestine, could indeed control the very early steps of CDI by killing C. difficile bacilli at their germination site. As a consequence, HD5 can be regarded as a good candidate for the containment of hypervirulent C. difficile strains, and it could be exploited in the therapy of CDI and relapsing C. difficile-associated disease.
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62
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Into T, Takigawa T, Niida S, Shibata KI. MyD88 deficiency alters expression of antimicrobial factors in mouse salivary glands. PLoS One 2014; 9:e113333. [PMID: 25415419 PMCID: PMC4240645 DOI: 10.1371/journal.pone.0113333] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 10/27/2014] [Indexed: 02/06/2023] Open
Abstract
The surfaces of oral mucosa are protected from infections by antimicrobial proteins and natural immunoglobulins that are constantly secreted in saliva, serving as principal innate immune defense in the oral cavity. MyD88 is an important adaptor protein for signal transduction downstream of Toll-like receptors and TACI, receptors for regulation of innate immunity and B cell responses, respectively. Although MyD88-mediated signaling has a regulatory role in the intestinal mucosal immunity, its specific role in the oral cavity has remained elusive. In the present study, we assessed the influence of MyD88 deficiency on the oral innate defense, particularly the expression of antimicrobial proteins in salivary glands and production of salivary basal immunoglobulins, in mice. Microarray analysis of the whole tissues of submandibular glands revealed that the expression of several genes encoding salivary antimicrobial proteins, such as secretory leukocyte peptidase inhibitor (SLPI), S100A8, and lactotransferrin, was reduced due to MyD88 deficiency. Histologically, SLPI-expressing acinar cells were evidently decreased in the glands from MyD88 deficient mice compared to wild-type mice. Flow cytometric analysis revealed that B cell populations, including B-1 cells and IgA+ plasma cells, residing in submandibular glands were increased by MyD88 deficiency. The level of salivary anti-phosphorylcholine IgA was elevated in MyD88 deficient mice compared to wild-type mice. Thus, this study provides a detailed description of the effect of MyD88 deficiency on expression of several salivary antimicrobial factors in mice, illustrating the role for MyD88-mediated signaling in the innate immune defense in the oral cavity.
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Affiliation(s)
- Takeshi Into
- Department of Oral Microbiology, Division of Oral Infections and Health Sciences, Asahi University School of Dentistry, Gifu, Japan
- * E-mail:
| | - Toshiya Takigawa
- Department of Oral Anatomy, Division of Oral Structure, Function and Development, Asahi University School of Dentistry, Gifu, Japan
| | - Shumpei Niida
- Laboratory of Genomics and Proteomics, National Center for Geriatrics and Gerontology (NCGG), Aichi, Japan
| | - Ken-ichiro Shibata
- Laboratory of Oral Molecular Microbiology, Department of Oral Pathobiological Science, Hokkaido University Graduate School of Dental Medicine, Hokkaido, Japan
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63
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McClure R, Massari P. TLR-Dependent Human Mucosal Epithelial Cell Responses to Microbial Pathogens. Front Immunol 2014; 5:386. [PMID: 25161655 PMCID: PMC4129373 DOI: 10.3389/fimmu.2014.00386] [Citation(s) in RCA: 191] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 07/29/2014] [Indexed: 12/17/2022] Open
Abstract
Toll-like receptor (TLR) signaling represents one of the best studied pathways to implement defense mechanisms against invading microbes in human being as well as in animals. TLRs respond to specific microbial ligands and to danger signals produced by the host during infection, and initiate downstream cascades that activate both innate and adaptive immunity. TLRs are expressed by professional immune cells and by the large majority of non-hematopoietic cells, including epithelial cells. In epithelial tissues, TLR functions are particularly important because these sites are constantly exposed to microorganisms, due to their location at the host interface with the environment. While at these sites specific defense mechanisms and inflammatory responses are initiated via TLR signaling against pathogens, suppression or lack of TLR activation is also observed in response to the commensal microbiota. The mechanisms by which TLR signaling is regulated in mucosal epithelial cells include differential expression and levels of TLRs (and their signaling partners), their cellular localization and positioning within the tissue in a fashion that favors responses to pathogens while dampening responses to commensals and maintaining tissue homeostasis in physiologic conditions. In this review, the expression and activation of TLRs in mucosal epithelial cells of several sites of the human body are examined. Specifically, the oral cavity, the ear canal and eye, the airways, the gut, and the reproductive tract are discussed, along with how site-specific host defense mechanisms are implemented via TLR signaling.
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Affiliation(s)
- Ryan McClure
- Department of Microbiology, Boston University School of Medicine , Boston, MA , USA
| | - Paola Massari
- Section of Infectious Diseases, Department of Medicine, Boston University School of Medicine , Boston, MA , USA
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Khoruts A, Weingarden AR. Emergence of fecal microbiota transplantation as an approach to repair disrupted microbial gut ecology. Immunol Lett 2014; 162:77-81. [PMID: 25106113 DOI: 10.1016/j.imlet.2014.07.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 07/22/2014] [Accepted: 07/29/2014] [Indexed: 02/07/2023]
Abstract
In the recent years fecal microbiota transplantation (FMT) has emerged as an effective therapeutic option for patients with refractory Clostridium difficile infection that is not responding to antibiotic therapy. It results in implantation of donor microbiota into recipients and restoration of normal distal gut microbial community structure. We anticipate that this form of therapy represents merely the first entry into a new class of therapeutics. There is great interest in application of FMT or defined microbial consortia to treatment of many diseases associated with dysbiosis. However, many challenges remain in development as our understanding of microbial ecology within the human body and microbiota-host interactions remain limited. Future advances in this field will be critically depending on detailed mechanistic understanding.
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Affiliation(s)
- Alexander Khoruts
- Department of Medicine, Center for Immunology, University of Minnesota, United States; BioTechnology Institute, University of Minnesota, United States.
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65
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Petrof EO, Khoruts A. From stool transplants to next-generation microbiota therapeutics. Gastroenterology 2014; 146:1573-1582. [PMID: 24412527 PMCID: PMC4221437 DOI: 10.1053/j.gastro.2014.01.004] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 12/23/2013] [Accepted: 01/06/2014] [Indexed: 12/19/2022]
Abstract
The epidemic of Clostridium difficile infection fueled by new virulent strains of the organism has led to increased use of fecal microbiota transplantation (FMT). The procedure is effective for even the most desperate cases after failure of multiple courses of antibiotics. The approach recognizes microbiota to be integral to normal human physiology, and microbiota being used in FMT represents a new class of therapeutics. Imbalance in the composition and altered activity of the microbiota are associated with many diseases. Consequently, there is growing interest in applying FMT to non-C difficile indications. However, this may succeed only if microbiota therapeutics are developed systematically, based on mechanistic understanding, and applying up-to-date principles of microbial ecology. We discuss 2 pathways in the development of this new therapeutic class: whole microbial communities separated from donor stool and an assembly of specific fecal microorganisms grown in vitro.
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Affiliation(s)
- Elaine O. Petrof
- Department of Medicine, Division of Infectious Diseases & Gastrointestinal Research Unit; Queens University and Kingston General Hospital, Kingston, ON, Canada
| | - Alexander Khoruts
- Center for Immunology and Department of Medicine, Division of Gastroenterology; University of Minnesota, MN, USA
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66
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Stockinger S, Albers T, Duerr CU, Ménard S, Pütsep K, Andersson M, Hornef MW. Interleukin-13-mediated paneth cell degranulation and antimicrobial peptide release. J Innate Immun 2014; 6:530-41. [PMID: 24556597 DOI: 10.1159/000357644] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 11/30/2013] [Indexed: 12/18/2022] Open
Abstract
Paneth cell-derived enteric antimicrobial peptides significantly contribute to antibacterial host defense and host-microbial homeostasis. Regulation occurs by enzymatic processing and release into the small intestinal lumen, but the stimuli involved are incompletely understood. Here, the capacity of various microbial and immune stimuli to induce antimicrobial peptide release from small intestinal tissue was systematically evaluated using antibacterial activity testing, immunostaining for Paneth cell granules and mass spectrometry. We confirmed the stimulatory activity of the muscarinic receptor agonist carbachol and the nucleotide-binding oligomerization domain ligand muramyl dipeptide. In contrast, no release of antibacterial activity was noted after treatment with the Toll-like receptor ligands poly(I:C), lipopolysaccharide or CpG, and the cytokines interleukin (IL)-15, IL-22, IL-28 and interferon-γ. Rapid Paneth cell degranulation and antimicrobial activity release, however, was observed after stimulation with the endogenous mediators IL-4 and IL-13. This process required phosphatidylinositol 3-kinase and was associated with protein kinase B phosphorylation in Paneth cells. Flow cytometric analysis confirmed expression of the IL-13 receptor α1 on isolated Paneth cells. Our findings identify a novel role of IL-13 as inducer of Paneth cell degranulation and enteric antimicrobial peptide release. IL-13 may thus contribute to mucosal antimicrobial host defense and host microbial homeostasis.
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Affiliation(s)
- Silvia Stockinger
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
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Brown EM, Sadarangani M, Finlay BB. The role of the immune system in governing host-microbe interactions in the intestine. Nat Immunol 2013; 14:660-7. [PMID: 23778793 DOI: 10.1038/ni.2611] [Citation(s) in RCA: 260] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 04/11/2013] [Indexed: 02/08/2023]
Abstract
The mammalian intestinal tract harbors a diverse community of trillions of microorganisms, which have co-evolved with the host immune system for millions of years. Many of these microorganisms perform functions critical for host physiology, but the host must remain vigilant to control the microbial community so that the symbiotic nature of the relationship is maintained. To facilitate homeostasis, the immune system ensures that the diverse microbial load is tolerated and anatomically contained, while remaining responsive to microbial breaches and invasion. Although the microbiota is required for intestinal immune development, immune responses also regulate the structure and composition of the intestinal microbiota. Here we discuss recent advances in our understanding of these complex interactions and their implications for human health and disease.
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Affiliation(s)
- Eric M Brown
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
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Abstract
Paneth cells are highly specialized epithelial cells of the small intestine, where they coordinate many physiological functions. First identified more than a century ago on the basis of their readily discernible secretory granules by routine histology, these cells are located at the base of the crypts of Lieberkühn, tiny invaginations that line the mucosal surface all along the small intestine. Investigations over the past several decades determined that these cells synthesize and secrete substantial quantities of antimicrobial peptides and proteins. More recent studies have determined that these antimicrobial molecules are key mediators of host-microbe interactions, including homeostatic balance with colonizing microbiota and innate immune protection from enteric pathogens. Perhaps more intriguing, Paneth cells secrete factors that help sustain and modulate the epithelial stem and progenitor cells that cohabitate in the crypts and rejuvenate the small intestinal epithelium. Dysfunction of Paneth cell biology contributes to the pathogenesis of chronic inflammatory bowel disease.
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Affiliation(s)
- Hans C Clevers
- Hubrecht Institute-KNAW, University Medical Center Utrecht, Uppsalalaan, Utrecht 3584CT, The Netherlands.
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Kamdar K, Nguyen V, DePaolo RW. Toll-like receptor signaling and regulation of intestinal immunity. Virulence 2013; 4:207-12. [PMID: 23334153 PMCID: PMC3711978 DOI: 10.4161/viru.23354] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The intestine is a complex organ that must maintain tolerance to innocuous food antigens and commensal microbiota while being also able to mount inflammatory responses against invading pathogenic microorganisms. The ability to restrain tolerogenic responses while permitting inflammatory responses requires communication between commensal bacteria, intestinal epithelial cells and immune cells. Disruption or improper signaling between any of these factors may lead to uncontrolled inflammation and the development of inflammatory diseases. Toll-like receptors (TLR) recognize conserved molecular motifs of microorganisms and, not surprisingly, are important for maintaining tolerance to commensal microbiota, as well as inducing inflammation against pathogens. Perturbations in individual TLR signaling can lead to a number of different outcomes and illustrate a system of regulation within the intestine in which each TLR plays a largely non-redundant role in mucosal immunity. This review will discuss recent findings on the roles of individual TLRs and intestinal homeostasis.
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Affiliation(s)
- Karishma Kamdar
- Department of Microbiology and Immunology, University of Southern California, Keck School of Medicine, Los Angeles, CA, USA
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