Dietary Selenium in Immune Mechanisms During an Enteric Bacterial Infection (OR12-08-19)

Abstract Objectives Enteropathogenic Escherichia coli (EPEC) poses a great threat to developing countries, as EPEC can result in diarrhea and colitis in children. Interestingly, the effect of trace element nutritional deficiencies as well as their supplementation on disease pathogenesis is increasingly being recognized. We have previously reported that supplementation of mice with selenium (Se), a trace element that is incorporated into selenoproteins as the 21st amino acid, resulted in the amelioration of chemically induced colitis through the downregulation of pro-inflammatory mediators of the arachidonic acid pathway, including prostaglandin E2 (PGE2). Here we examined the effects of Se supplementation on immune responses during an enteric infection with Citrobacter rodentium, a natural murine enteropathogen. Methods C57BL/6 mice placed on Se-deficient (0.01 ppm Se), Se-adequate (0.08 ppm Se), or Se-supplemented (0.4 ppm Se) diets for 8 weeks were infected with Citrobacter rodentium, the murine equivalent of EPEC with a shared core set of virulence factors. Mice were euthanized, and colons were collected for further analysis including western blots and flow cytometry. Results Se-deficient mice experienced increased bacterial burden, mortality, and decreased colon length following infection, compared to Se-adequate and Se-supplemented mice. Studies revealed that there was an increase type 3 innate-lymphoid cells (ILC3s) and IL-22 producing T helper 17 (Th17) cells, but a decrease in regulatory T- cells (Tregs) and 15-prostaglandin dehydrogenase (15-PGDH), the enzyme that preferentially oxidizes PGE2, in the colon of Se-deficient mice compared to Se-adequate and Se-supplemented mice. Treatment of Se-adequate mice with CAY10397, an inhibitor of 15-PGDH, increased the bacterial burden following infection. Infection of mice that lack expression of selenoproteins in macrophages (Trspfl/fl LysMCre) showed increased mortality despite being fed diets replete with Se. Conclusions Adequate to supplemental levels of dietary Se is required to maximize the expression of selenoproteins to effectively mediate resolution of enteric infections. Selenoproteins act through diverse mechanisms, including modulation of immune responses and inflammation through the oxidative metabolism of PGE2. Funding Sources National Institute of Health.

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Maintenance of Type 2 Response by CXCR6-Deficient ILC2 in Papain-Induced Lung Inflammation

International Journal of Molecular Sciences ◽

10.3390/ijms20215493 ◽

2019 ◽

Vol 20 (21) ◽

pp. 5493 ◽

Cited By ~ 1

Author(s):

Meunier ◽

Chea ◽

Garrido ◽

Perchet ◽

Petit ◽

...

Keyword(s):

Immune Response ◽

Immune Responses ◽

Nk Cell ◽

Lymphoid Cells ◽

Inflammatory Conditions ◽

Airway Diseases ◽

Type 2 Cytokines ◽

Lymphoid Organogenesis ◽

Deficient Mice

Innate lymphoid cells (ILC) are important players of early immune defenses in situations like lymphoid organogenesis or in case of immune response to inflammation, infection and cancer. Th1 and Th2 antagonism is crucial for the regulation of immune responses, however mechanisms are still unclear for ILC functions. ILC2 and NK cells were reported to be both involved in allergic airway diseases and were shown to be able to interplay in the regulation of the immune response. CXCR6 is a common chemokine receptor expressed by all ILC, and its deficiency affects ILC2 and ILC1/NK cell numbers and functions in lungs in both steady-state and inflammatory conditions. We determined that the absence of a specific ILC2 KLRG1+ST2– subset in CXCR6-deficient mice is probably dependent on CXCR6 for its recruitment to the lung under inflammation. We show that despite their decreased numbers, lung CXCR6-deficient ILC2 are even more activated cells producing large amount of type 2 cytokines that could drive eosinophilia. This is strongly associated to the decrease of the lung Th1 response in CXCR6-deficient mice.

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Gamma Interferon Produced by Antigen-Specific CD4+ T Cells Regulates the Mucosal Immune Responses to Citrobacter rodentium Infection

Infection and Immunity ◽

10.1128/iai.01343-09 ◽

2010 ◽

Vol 78 (6) ◽

pp. 2653-2666 ◽

Cited By ~ 45

Author(s):

Hideyuki Shiomi ◽

Atsuhiro Masuda ◽

Shin Nishiumi ◽

Masayuki Nishida ◽

Tetsuya Takagawa ◽

...

Keyword(s):

T Cells ◽

Immune Responses ◽

Gamma Interferon ◽

Immune Defense ◽

Interleukin 4 ◽

Mucosal Inflammation ◽

Citrobacter Rodentium ◽

Macrophage Phagocytosis ◽

Ifn Γ ◽

Deficient Mice

ABSTRACT Citrobacter rodentium, a murine model pathogen for enteropathogenic Escherichia coli, colonizes the surface of intestinal epithelial cells and causes mucosal inflammation. This bacterium is an ideal model for investigating pathogen-host immune interactions in the gut. It is well known that gene transcripts for Th1 cytokines are highly induced in colonic tissue from mice infected with C. rodentium. However, it remains to be seen whether the Th1 or Th2 cytokines produced by antigen-specific CD4+ T cells provide effective regulation of the host immune defense against C. rodentium infection. To investigate the antigen-specific immune responses, C. rodentium expressing ovalbumin (OVA-C. rodentium), a model antigen, was generated and used to define antigen-specific responses under gamma interferon (IFN-γ)-deficient or interleukin-4 (IL-4)-deficient conditions in vivo. The activation of antigen-specific CD4+ T cells and macrophage phagocytosis were evaluated in the presence of IFN-γ or IL-4 in vitro. IFN-γ-deficient mice exhibited a loss of body weight and a higher bacterial concentration in feces during OVA-C. rodentium infection than C57BL/6 (wild type) or IL-4-deficient mice. This occurred through the decreased efficiency of macrophage phagocytosis and the activation of antigen-specific CD4+ T cells. Furthermore, a deficiency in antigen-specific CD4+ T-cell-expressed IFN-γ led to a higher susceptibility to mucosal and gut-derived systemic OVA-C. rodentium infection. These results show that the IFN-γ produced by antigen-specific CD4+ T cells plays an important role in the defense against C. rodentium.

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Pathogenesis and Persistence of Increased Epithelial Mucosubstances in the Nasal Airways of Rats and Mice Episodically Exposed to Ethylene

Toxicologic Pathology ◽

10.1177/0192623320960459 ◽

2020 ◽

Vol 48 (7) ◽

pp. 875-886

Author(s):

Jack R. Harkema ◽

Elyse A. Eldridge ◽

Amy Freeland ◽

Daven Jackson-Humbles ◽

Ryan A. Lewandowski ◽

...

Keyword(s):

Immune Responses ◽

Mucous Cell ◽

Airway Disease ◽

Lymphoid Cells ◽

Nasal Airway ◽

Cell Hyperplasia ◽

Mucus Production ◽

Nasal Airways ◽

Rats And Mice ◽

Deficient Mice

Rats repeatedly exposed to high airborne concentrations of ethylene develop eosinophilic rhinitis and mucous cell hyperplasia/hypertrophy (MCH) in nasal respiratory epithelium. Mechanisms underlying these lesions are not well understood to inform occupational exposure guidelines. In this study, we determined (1) the nasal histopathology in rats episodically exposed to ethylene, (2) the ethylene-induced nasal histopathology in similarly exposed mice, and (3) how innate lymphoid cells (ILCs) play a role in ethylene-induced MCH. Animals were exposed to 0 or 10,000 ppm ethylene, 6 h/d, 5 d/wk, for 2 weeks and sacrificed 1 day or 2 weeks postexposure. Others received three 2-week exposure blocks separated by 2-week intervals of no exposure. Episodic exposure was chosen to aid in distinguishing irritant from immune responses. Mucous cell hyperplasia/hypertrophy was induced by ethylene in both species. Rats developed a mild, but transient, eosinophilic rhinitis. Mucous cell hyperplasia/hypertrophy was transient in mice, but persistent in rats. Increases in epithelial mucosubstances after 2 weeks of exposure were only present in ILC-sufficient mice, but not in ILC-deficient mice suggesting that ILCs play a role in MCH and overexpression of genes associated with mucus production/secretion. These findings in animals suggest that inhaled ethylene does not act as a sensitizing agent and will not induce allergen-like nasal airway disease.

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Enhanced Susceptibility to Citrobacter rodentium Infection in MicroRNA-155-Deficient Mice

Infection and Immunity ◽

10.1128/iai.00969-12 ◽

2012 ◽

Vol 81 (3) ◽

pp. 723-732 ◽

Cited By ~ 31

Author(s):

Simon Clare ◽

Victoria John ◽

Alan W. Walker ◽

Jennifer L. Hill ◽

Cei Abreu-Goodger ◽

...

Keyword(s):

Immune Responses ◽

Bacterial Pathogen ◽

Citrobacter Rodentium ◽

Wild Type ◽

Content Type ◽

Humoral Immune ◽

Humoral Immune Responses ◽

Control Gene Expression ◽

Gastrointestinal Tissue ◽

Deficient Mice

ABSTRACTMicroRNAs (miRNAs) are small noncoding molecules that control gene expression posttranscriptionally, with microRNA-155 (miR-155) one of the first to be implicated in immune regulation. Here, we show that miR-155-deficient mice are less able to eradicate a mucosalCitrobacter rodentiuminfection than wild-type C57BL/6 mice. miR-155-deficient mice exhibited prolonged colonization associated with a higherC. rodentiumburden in gastrointestinal tissue and spread into systemic tissues. Germinal center formation and humoral immune responses againstC. rodentiumwere severely impaired in infected miR-155-deficient mice. A similarly susceptible phenotype was observed in μMT mice reconstituted with miR-155-deficient B cells, indicating that miR-155 is required intrinsically for mediating protection against this predominantly luminal bacterial pathogen.

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Attenuation of Intestinal Inflammation in Interleukin-10-Deficient Mice Infected with Citrobacter rodentium

Infection and Immunity ◽

10.1128/iai.00066-14 ◽

2014 ◽

Vol 82 (5) ◽

pp. 1949-1958 ◽

Cited By ~ 16

Author(s):

Sara M. Dann ◽

Christine Le ◽

Barun K. Choudhury ◽

Houpu Liu ◽

Omar Saldarriaga ◽

...

Keyword(s):

Immune Responses ◽

Intestinal Inflammation ◽

Acute Infection ◽

Interleukin 10 ◽

Mucosal Inflammation ◽

Immune Functions ◽

Citrobacter Rodentium ◽

Microbial Infection ◽

Content Type ◽

Deficient Mice

ABSTRACTInterleukin-10 (IL-10) curtails immune responses to microbial infection and autoantigens and contributes to intestinal immune homeostasis, yet administration of IL-10 has not been effective at attenuating chronic intestinal inflammatory conditions, suggesting that its immune functions may be context dependent. To gain a broader understanding of the importance of IL-10 in controlling mucosal immune responses to infectious challenges, we employed the murine attaching and effacing pathogenCitrobacter rodentium, which colonizes primarily the surfaces of the cecum and colon and causes transient mucosal inflammation driven by Th17 and Th1 T helper cells. Infection induced macrophage and dendritic cell production of IL-10, which diminished antibacterial host defenses, because IL-10-deficient mice cleared infection faster than wild-type controls. In parallel, the mice had less acute infection-associated colitis and resolved it more rapidly than controls. Importantly, transientC. rodentiuminfection protected IL-10-deficient mice against the later development of spontaneous colitis that normally occurs with aging in these mice. Genome-wide expression studies revealed that IL-10 deficiency was associated with downregulation of proinflammatory pathways but increased expression of the anti-inflammatory cytokine IL-27 in response to infection. IL-27 was found to suppressin vitroTh17 and, to a lesser degree, Th1 differentiation independent of IL-10. Furthermore, neutralization of IL-27 resulted in more severe colitis in infected IL-10-deficient mice. Together, these findings indicate that IL-10 is dispensable for resolvingC. rodentium-associated colitis and further suggest that IL-27 may be a critical factor for controlling intestinal inflammation and Th17 and Th1 development by IL-10-independent mechanisms.

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Sensory Nociceptive Neurons Contribute to Host Protection During Enteric Infection With Citrobacter rodentium

The Journal of Infectious Diseases ◽

10.1093/infdis/jiaa014 ◽

2020 ◽

Vol 221 (12) ◽

pp. 1978-1988 ◽

Cited By ~ 1

Author(s):

Valerie T Ramirez ◽

Jessica Sladek ◽

Dayn Romero Godinez ◽

Kavi M Rude ◽

Pamela Chicco ◽

...

Keyword(s):

Bacterial Pathogens ◽

Protective Role ◽

The Body ◽

Enteric Infection ◽

Receptor Signaling ◽

Bacterial Burden ◽

Citrobacter Rodentium ◽

Cgrp Receptor ◽

Nociceptive Neurons

Abstract Background Neurons are an integral component of the immune system that functions to coordinate responses to bacterial pathogens. Sensory nociceptive neurons that can detect bacterial pathogens are found throughout the body with dense innervation of the intestinal tract. Methods In this study, we assessed the role of these nerves in the coordination of host defenses to Citrobacter rodentium. Selective ablation of nociceptive neurons significantly increased bacterial burden 10 days postinfection and delayed pathogen clearance. Results Because the sensory neuropeptide CGRP (calcitonin gene-related peptide) regulates host responses during infection of the skin, lung, and small intestine, we assessed the role of CGRP receptor signaling during C rodentium infection. Although CGRP receptor blockade reduced certain proinflammatory gene expression, bacterial burden and Il-22 expression was unaffected. Conclusions Our data highlight that sensory nociceptive neurons exert a significant host protective role during C rodentium infection, independent of CGRP receptor signaling.

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Nasal alum-adjuvanted vaccine promotes IL-33 release from alveolar epithelial cells that elicits IgA production via type 2 immune responses

PLoS Pathogens ◽

10.1371/journal.ppat.1009890 ◽

2021 ◽

Vol 17 (8) ◽

pp. e1009890

Author(s):

Eita Sasaki ◽

Hideki Asanuma ◽

Haruka Momose ◽

Keiko Furuhata ◽

Takuo Mizukami ◽

...

Keyword(s):

Epithelial Cell ◽

Immune Responses ◽

Mhc Class Ii ◽

T Cell Activation ◽

Cultured Cells ◽

Alveolar Epithelial Cell ◽

Lymphoid Cells ◽

Alveolar Epithelial Cells ◽

Alveolar Epithelial ◽

Deficient Mice

Aluminum hydroxide salts (alum) have been added to inactivated vaccines as safe and effective adjuvants to increase the effectiveness of vaccination. However, the exact cell types and immunological factors that initiate mucosal immune responses to alum adjuvants are unclear. In this study, the mechanism of action of alum adjuvant in nasal vaccination was investigated. Alum has been shown to act as a powerful and unique adjuvant when added to a nasal influenza split vaccine in mice. Alum is cytotoxic in the alveoli and stimulates the release of damage-associated molecular patterns, such as dsDNA, interleukin (IL)-1α, and IL-33. We found that Ag-specific IgA antibody (Ab) production was markedly reduced in IL-33-deficient mice. However, no decrease was observed in Ag-specific IgA Ab production with DNase I treatment, and no decrease was observed in IL-1α/β or IL-6 production in IL-33-deficient mice. From the experimental results of primary cultured cells and immunofluorescence staining, although IL-1α was secreted by alveolar macrophage necroptosis, IL-33 release was observed in alveolar epithelial cell necroptosis but not in alveolar macrophages. Alum- or IL-33-dependent Ag uptake enhancement and elevation of OX40L expression were not observed. By stimulating the release of IL-33, alum induced Th2 immunity via IL-5 and IL-13 production in group 2 innate lymphoid cells (ILC2s) and increased MHC class II expression in antigen-presenting cells (APCs) in the lung. Our results suggest that IL-33 secretion by epithelial cell necroptosis initiates APC- and ILC2-mediated T cell activation, which is important for the enhancement of Ag-specific IgA Ab production by alum.

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A Bovine Enteric Mycobacterium Infection Model to Analyze Parenteral Vaccine-Induced Mucosal Immunity and Accelerate Vaccine Discovery

Frontiers in Immunology ◽

10.3389/fimmu.2020.586659 ◽

2020 ◽

Vol 11 ◽

Author(s):

Antonio Facciuolo ◽

Amy H. Lee ◽

Michael J. Trimble ◽

Neil Rawlyk ◽

Hugh G. G. Townsend ◽

...

Keyword(s):

Small Intestine ◽

Immune Responses ◽

Vaccine Development ◽

Natural Host ◽

Lymphoid Cells ◽

Intestinal Lumen ◽

Infection Model ◽

Enteric Infection ◽

Intestinal Segments ◽

Mucosal Immune Responses

Mycobacterial diseases of cattle are responsible for considerable production losses worldwide. In addition to their importance in animals, these infections offer a nuanced approach to understanding persistent mycobacterial infection in native host species. Mycobacteriumavium ssp. paratuberculosis (MAP) is an enteric pathogen that establishes a persistent, asymptomatic infection in the small intestine. Difficulty in reproducing infection in surrogate animal models and limited understanding of mucosal immune responses that control enteric infection in the natural host have been major barriers to MAP vaccine development. We previously developed a reproducible challenge model to establish a consistent MAP infection using surgically isolated intestinal segments prepared in neonatal calves. In the current study, we evaluated whether intestinal segments could be used to screen parenteral vaccines that alter mucosal immune responses to MAP infection. Using Silirum® – a commercial MAP bacterin – we demonstrate that intestinal segments provide a platform for assessing vaccine efficacy within a relatively rapid period of 28 days post-infection. Significant differences between vaccinates and non-vaccinates could be detected using quantitative metrics including bacterial burden in intestinal tissue, MAP shedding into the intestinal lumen, and vaccine-induced mucosal immune responses. Comparing vaccine-induced responses in mucosal leukocytes isolated from the site of enteric infection versus blood leukocytes revealed substantial inconsistences between these immune compartments. Moreover, parenteral vaccination with Silirum did not induce equal levels of protection throughout the small intestine. Significant control of MAP infection was observed in the continuous but not the discrete Peyer’s patches. Analysis of these regional mucosal immune responses revealed novel correlates of immune protection associated with reduced infection that included an increased frequency of CD335+ innate lymphoid cells, and increased expression of IL21 and IL27. Thus, intestinal segments provide a novel model to accelerate vaccine screening and discovery by testing vaccines directly in the natural host and provides a unique opportunity to interrogate mucosal immune responses to mycobacterial infections.

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