Salmonella-superspreader hosts require gut regulatory T cells to maintain a disease tolerant state
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE303864 | GEO | 2025/08/19
REPOSITORIES: GEO
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Project description:Host-pathogen interactions involve two critical strategies: resistance, whereby hosts clear invading microbes, and tolerance, whereby hosts carry high pathogen burden asymptomatically. Here, we investigate mechanisms by which Salmonella- superspreader hosts (SSP) maintain an asymptomatic state during chronic infection. We found that regulatory T cells (Tregs) are essential for this disease-tolerant state, limiting intestinal immunopathology and enabling SSP hosts to thrive, while facilitating Salmonella transmission. Treg depletion in SSP mice resulted in decreased survival, heightened gut inflammation and impairment of the intestinal barrier, without affecting Salmonella persistence. Colonic Tregs from SSP mice exhibited a unique transcriptomic profile characterized by the upregulation type-1 inflammatory genes, including the transcription factor T-bet. In the absence of Tregs, we observed robust expansion of cytotoxic CD4+ T cells, with CD4+ T cell depletion restoring homeostasis. These results uncover a critical host strategy to establish disease tolerance during chronic enteric infection, providing novel insights into mucosal responses to persistent pathogens and chronic intestinal inflammation.
2025-08-19 | GSE302695 | GEO
Project description:During the colonization of hosts, bacterial pathogens are presented with many challenges that must be overcome for colonization to successfully occur. This requires bacterial sensing of the surroundings and adaptation to the conditions encountered. One of the major impediments to pathogen colonization of the mammalian gastrointestinal tract is the antibacterial action of bile. Salmonella enterica serovar Typhimurium has specific mechanisms involved in resistance to bile. Besides being resistant to it, Salmonella can also successfully multiply in bile, using it as a source of nutrients. This accomplishment is highly relevant to pathogenesis, as Salmonella colonizes the gallbladder of hosts, where it can be carried asymptomatically and promote further host spread and transmission. In order to gain insights into the mechanisms used by Salmonella to grow in bile, we studied the changes elicited by Salmonella in the chemical composition of bile during growth in vitro and in vivo through a metabolomics approach. Our data suggest that phospholipids are an important source of carbon and energy for Salmonella during growth in the laboratory as well as during gallbladder infections of mice. Further studies in this area will generate a better understanding of how Salmonella exploits this generally hostile environment for its own benefit.
2011-07-07 | GSE30404 | GEO
Project description:Examination of intestinal colonization of enteric pathogen Salmonella typhimurium
2015-08-14 | MSV000079240 | MassIVE
Project description:Type I interferons (IFNs) exert a broad range of biological effects important in coordinating immune responses, which have classically been studied in the context of pathogen clearance. Yet, whether immunomodulatory bacteria operate through IFN pathways to support intestinal immune tolerance remains elusive. Here, we reveal that the commensal bacterium, Bacteroides fragilis, utilizes canonical antiviral pathways to modulate intestinal dendritic cells (DCs) and regulatory T cell (Treg) responses. Specifically, IFN signaling is required for commensal-induced tolerance, as IFNAR1-deficient DCs display blunted IL-10 and IL-27 production in response to B. fragilis. We further establish that IFN-driven IL-27 in DCs is critical in shaping the ensuing Foxp3+ Treg via IL27Ra signaling. Consistent with these findings, single cell RNA sequencing of gut Tregs demonstrated that colonization with B. fragilis promotes a distinct IFN gene signature in Foxp3+ Tregs during intestinal inflammation. Altogether, our findings demonstrate a critical role of commensal-mediated immune tolerance via tonic type I IFN signaling.
2023-12-05 | GSE248021 | GEO
Project description:This is system 1, the model with linear antigen uptake by pAPCs, described in the article:
Self-tolerance and Autoimmunity in a Regulatory T Cell Model.
Alexander HK, Wahl LM.
Bull Math Biol. 2010 Mar 2.
PMID:20195912, doi:10.1007/s11538-010-9519-2;
Abstract:
The class of immunosuppressive lymphocytes known as regulatory T cells (Tregs) has been identified as a key component in preventing autoimmune diseases. Although Tregs have been incorporated previously in mathematical models of autoimmunity, we take a novel approach which emphasizes the importance of professional antigen presenting cells (pAPCs). We examine three possible mechanisms of Treg action (each in isolation) through ordinary differential equation (ODE) models. The immune response against a particular autoantigen is suppressed both by Tregs specific for that antigen and by Tregs of arbitrary specificities, through their action on either maturing or already mature pAPCs or on autoreactive effector T cells. In this deterministic approach, we find that qualitative long-term behaviour is predicted by the basic reproductive ratio R (0) for each system. When R (0) 1, this equilibrium loses its stability and a stable non-trivial equilibrium appears. We interpret the absence of self-damaging populations at the trivial equilibrium to imply a state of self-tolerance, and their presence at the non-trivial equilibrium to imply a state of chronic autoimmunity. Irrespective of mechanism, our model predicts that Tregs specific for the autoantigen in question play no role in the system's qualitative long-term behaviour, but have quantitative effects that could potentially reduce an autoimmune response to sub-clinical levels. Our results also suggest an important role for Tregs of arbitrary specificities in modulating the qualitative outcome. A stochastic treatment of the same model demonstrates that the probability of developing a chronic autoimmune response increases with the initial exposure to self antigen or autoreactive effector T cells. The three different mechanisms we consider, while leading to a number of similar predictions, also exhibit key differences in both transient dynamics (ODE approach) and the probability of chronic autoimmunity (stochastic approach).
Originally created by libAntimony v1.4 (using libSBML 3.4.1)
2024-09-02 | BIOMD0000000289 | BioModels
Project description:This is system 2, the model with Michelis Menten type antigen uptake by pAPCs, described in the article:
Self-tolerance and Autoimmunity in a Regulatory T Cell Model.
Alexander HK, Wahl LM. Bull Math Biol.
2010 Mar 2.
PMID: 20195912
, doi: 10.1007/s11538-010-9519-2
;
Abstract:
The class of immunosuppressive lymphocytes known as regulatory T cells (Tregs) has been identified as a key component in preventing autoimmune diseases. Although Tregs have been incorporated previously in mathematical models of autoimmunity, we take a novel approach which emphasizes the importance of professional antigen presenting cells (pAPCs). We examine three possible mechanisms of Treg action (each in isolation) through ordinary differential equation (ODE) models. The immune response against a particular autoantigen is suppressed both by Tregs specific for that antigen and by Tregs of arbitrary specificities, through their action on either maturing or already mature pAPCs or on autoreactive effector T cells. In this deterministic approach, we find that qualitative long-term behaviour is predicted by the basic reproductive ratio R (0) for each system. When R (0) 1, this equilibrium loses its stability and a stable non-trivial equilibrium appears. We interpret the absence of self-damaging populations at the trivial equilibrium to imply a state of self-tolerance, and their presence at the non-trivial equilibrium to imply a state of chronic autoimmunity. Irrespective of mechanism, our model predicts that Tregs specific for the autoantigen in question play no role in the system's qualitative long-term behaviour, but have quantitative effects that could potentially reduce an autoimmune response to sub-clinical levels. Our results also suggest an important role for Tregs of arbitrary specificities in modulating the qualitative outcome. A stochastic treatment of the same model demonstrates that the probability of developing a chronic autoimmune response increases with the initial exposure to self antigen or autoreactive effector T cells. The three different mechanisms we consider, while leading to a number of similar predictions, also exhibit key differences in both transient dynamics (ODE approach) and the probability of chronic autoimmunity (stochastic approach).
Originally created by libAntimony v1.4 (using libSBML 3.4.1)
2024-09-02 | BIOMD0000000290 | BioModels
Project description:During the colonization of hosts, bacterial pathogens are presented with many challenges that must be overcome for colonization to successfully occur. This requires bacterial sensing of the surroundings and adaptation to the conditions encountered. One of the major impediments to pathogen colonization of the mammalian gastrointestinal tract is the antibacterial action of bile. Salmonella enterica serovar Typhimurium has specific mechanisms involved in resistance to bile. Besides being resistant to it, Salmonella can also successfully multiply in bile, using it as a source of nutrients. This accomplishment is highly relevant to pathogenesis, as Salmonella colonizes the gallbladder of hosts, where it can be carried asymptomatically and promote further host spread and transmission. In order to gain insights into the mechanisms used by Salmonella to grow in bile, we studied the changes elicited by Salmonella in the chemical composition of bile during growth in vitro and in vivo through a metabolomics approach. Our data suggest that phospholipids are an important source of carbon and energy for Salmonella during growth in the laboratory as well as during gallbladder infections of mice. Further studies in this area will generate a better understanding of how Salmonella exploits this generally hostile environment for its own benefit. For in vitro studies, bile was extracted from C57BL/6 mice and used immediately. An overnight culture of Salmonella enterica serovar Typhimurium SL1344 was used to inoculate 10 ?L of bile at an approximate density of 5x10^6 cells/mL. The experiment was performed in duplicate, and a total of 2 uninfected and 2 infected bile samples were studied. Samples were incubated for 24 hours at 37 oC with shaking. After incubation, samples were centrifuged to remove bacteria and the supernatant was saved for metabolomic analyses. For in vivo studies, C57BL/6 mice were infected with approximately 10^8 bacterial cells by oral gavage. Four groups of three to four mice each were either infected with Salmonella or kept uninfected (total of 11 mice per treatment group). Five days after infection, all mice were sacrificed and bile was collected. Samples were centrifuged and supernatants saved for metabolomic analyses. Samples were prepared by mixing equal volumes of bile from three to four mice, generating three samples per treatment (uninfected and infected), which were used in the subsequent steps. Seven microliters of each sample was evaporated and the residue resuspended in 50% acetonitrine. Extracts were infused into a 12-T Apex-Qe hybrid quadrupole-FT-ICR mass spectrometer equipped with an Apollo II electrospray ionization source, a quadrupole mass filter and a hexapole collision cell. Raw mass spectrometry data were processed as described elsewhere (Han et al. 2008. Metabolomics. 4:128-140). To identify differences in metabolite composition between different groups of samples, we filtered the list of masses for metabolites which were present on one set of samples but not the other. Additionally, we calculated the ratios between averaged intensities of metabolites from each group of mice. To assign possible metabolite identities to the masses selected as described above, the monoisotopic neutral masses of interest were queried against the Human Metabolome Database (HMDB, http://www.hmdb.ca), with a tolerance of 0.001 Da.
2011-07-06 | E-GEOD-30404 | biostudies-arrayexpress
Project description:Regulatory T cells (Tregs) are immune cells that play a crucial role in maintaining tolerance to harmless antigens, including commensal microbes. In the intestine, Tregs can be classified into subsets based on their expression of transcription factors Helios, Rorg, Gata3 and cMaf. The exact functions of the intestinal Treg subsets and their role in maintaining tolerance to intestinal microbes is not fully understood. Here, we generated conditional knockout mice of each Treg subset and profiled the composition of their intestinal microbiota by performing 16S rRNA sequencing of stool from conditional knockouts and matched littermate controls.
2023-12-20 | GSE241887 | GEO
Project description:Foodborne illness from contaminated fresh produce has increased over the past decade, with the enteric human pathogen Salmonella enterica being frequently implicated in foodborne illness outbreaks associated with tomato consumption. Our previous work demonstrated that Salmonella responds to tomato cultivar differences, but knowledge of the underlying genetic responses is limited. To identify the mechanisms permitting this human pathogen-plant commodity association, a genome-wide transcriptomic analysis of Salmonella on tomato shoots and roots was conducted using an RNA-seq approach. Expression signal for 4,556 out of 4,745 annotated chromosomal and plasmid genes was obtained, indicating >96% coverage of the whole S. Typhimurium transcriptome. Identified key signals of differential expression related to cellular processes preserving viability while dealing with multiple biotic stresses and limited nutrient availability, compared to growth in nutrient-rich medium. Data suggest that sulfur metabolism, anaerobic respiration, nitrosative and oxidative stress tolerance and biofilm formation may be crucial functions for Salmonella survival on tomato. Some effector protein genes from pathogenicity island-2 were expressed, though their function in this niche is largely unknown. A large proportion of up-regulated genes remain uncharacterized, pointing to as yet undescribed strategies that allow enteric pathogens to associate with plants during transit in the environment to herbivorous hosts.
2016-09-17 | GSE73192 | GEO
Project description:CD4+Foxp3+ regulatory T cells (Tregs) play an essential role in suppressing transplant rejection but their role within the graft, is poorly understood. To address this, we compared phenotypic and transcriptomic characteristics of Treg populations within lymphoid-organs and grafts in an islet xenotransplant model of tolerance induced by co-stimulation blockade. In this study, Tregs were essential for tolerance induction and their numbers increased over time. Tregs demonstrated phenotypic and transcriptional heterogeneity within the graft, and lymphoid organs of tolerant mice. A sub-population of CD127highTreg with memory-like and suppressive features were present in high proportions within long surviving islet-grafts of tolerant mice and had a transcriptomic profile consistent with tissue-Tregs. Importantly these CD127highTregs were better able to prevent rejection by effector T cells, after adoptive transfer into secondary Rag-/- hosts, than naïve Tregs, or unselected Tregs isolated from tolerant mice. We propose that after initial development within the draining lymph node they undergo further genetic reprogramming within the graft towards a phenotype that has shared characteristics with other tissue or tumour Tregs. These findings provide a new focus for engineering such cells either in vivo or for adoptive transfer for inducing tolerance.
2024-03-22 | GSE220447 | GEO