Loss of self-tolerance leads to altered gene expression and IMD pathway activation in Drosophila melanogaster
Ontology highlight
ABSTRACT:
ORGANISM(S): Drosophila melanogaster
PROVIDER: GSE189383 | GEO | 2024/11/12
REPOSITORIES: GEO
Similar Datasets
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: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:Male gender is protective against multiple sclerosis and other T cell-mediated autoimmune diseases. This protection may be due, in part, to higher androgen levels in males. Androgen binds to the androgen receptor (AR) to regulate gene expression, but how androgen protects against autoimmunity is not well-understood. Autoimmune Regulator (Aire) prevents autoimmunity by promoting self-antigen expression in medullary thymic epithelial cells, such that developing T cells that recognize these self-antigens within the thymus undergo clonal deletion. Here, we show that androgen upregulates Aire-mediated thymic tolerance to protect against autoimmunity. Androgen recruits AR to Aire promoter regions, with consequent enhancement of Aire transcription. In mice and humans, thymic Aire expression is higher in males compared to females. Androgen administration and male gender protect against autoimmunity in a multiple sclerosis mouse model in an Aire-dependent manner. Thus, androgen control of an intrathymic Aire-mediated tolerance mechanism contributes to gender differences in autoimmunity. RNA-seq comparison of male vs. female expression in mTEC cells. Pools of 10 mice each were used for each replicate (two for male and two for female)
2016-03-09 | E-GEOD-79014 | biostudies-arrayexpress
Project description:Thymic central tolerance is essential to preventing autoimmunity. In medullary thymic epithelial cells (mTECs), the Autoimmune regulator (Aire) gene plays an essential role in this process by driving the expression of a diverse set of tissue-specific antigens (TSAs), which are presented and help tolerize self-reactive thymocytes. Interestingly, Aire has a highly tissue-restricted pattern of expression, with only mTECs and peripheral extrathymic Aire-expressing cells (eTACs) known to express detectable levels in adults. Despite this high level of tissue specificity, the cis-regulatory elements that control Aire expression have remained obscure. We used sequence conservation analysis and ChIP-seq against the enhancer-associated histone mark H3K27ac to identify a candidate Aire cis-regulatory element. There is enrichment of H3K27ac near this element, ACNS1, in mTECs and the element also has characteristics of being NF-κB-responsive. Finally, we find that this element is essential for Aire expression in vivo and necessary to prevent spontaneous autoimmunity, reflecting the importance of this regulatory DNA element in promoting immune tolerance. Two experimental groups (GFP neg mTECs and GFP pos mTECs), each with three samples, and one control sample (D10 Th2 cells).
2015-10-23 | E-GEOD-74257 | biostudies-arrayexpress
Project description:This micro-array helps establishing the function of Akirin, a nuclear protein with unknown domains, a putative interacting partner, in the transcriptional regulation of the targets of Relish, a NF-kB factor required to fight Gram(-) bacteria infection in Drosophila melanogaster. S2 cells were knocked down for Relish, Akirin and immune-challenged by Calcium-phosphate transient transfection of dsRNA and over-expressing PGRP-LC vector. Positively transfected cells were sorted by co-expressed Tomato and RNA was purified and analysed by a micro-array
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Project description:Male gender is protective against multiple sclerosis and other T cell-mediated autoimmune diseases. This protection may be due, in part, to higher androgen levels in males. Androgen binds to the androgen receptor (AR) to regulate gene expression, but how androgen protects against autoimmunity is not well-understood. Autoimmune Regulator (Aire) prevents autoimmunity by promoting self-antigen expression in medullary thymic epithelial cells, such that developing T cells that recognize these self-antigens within the thymus undergo clonal deletion. Here, we show that androgen upregulates Aire-mediated thymic tolerance to protect against autoimmunity. Androgen recruits AR to Aire promoter regions, with consequent enhancement of Aire transcription. In mice and humans, thymic Aire expression is higher in males compared to females. Androgen administration and male gender protect against autoimmunity in a multiple sclerosis mouse model in an Aire-dependent manner. Thus, androgen control of an intrathymic Aire-mediated tolerance mechanism contributes to gender differences in autoimmunity.
2016-03-09 | GSE79014 | GEO
Project description:Autoimmune diseases such as multiple sclerosis (MS) develop because of failed peripheral immune tolerance for a specific self-antigen (Ag). Numerous approaches for Ag-specific suppression of autoimmune neuroinflammation have been proven in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. One such approach is intravenous (i.v.) tolerance induction by injecting a myelin Ag used for EAE induction. However, the translation of this and similar experimental strategies into therapy for MS has been hampered by uncertainty regarding relevant myelin Ags in MS patients. To address this issue, we developed a therapeutic strategy that relies on oligodendrocyte (Ol)-derived extracellular vesicles (Ol-EVs), which naturally contain multiple myelin Ags. Ol-EVs injected i.v. suppressed disease in a myelin Ag-dependent manner, both prophylactically and therapeutically, in several EAE models. The treatment was safe and restored immune tolerance by inducing immunosuppressive monocytes and apoptosis of autoreactive encephalitogenic CD4+ T cells. Finally, we show that human Ols also release EVs containing most relevant myelin Ags, providing a basis for their use in MS therapy. These findings introduce an approach for suppressing central nervous system autoimmunity in a myelin Ag-specific manner.
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Project description:Long noncoding RNAs (lncRNAs), as a class of emerging regulators, play crucial role in regulating the strength and duration of innate immunity. However, little is known about how these Drosophila Imd immunity-related lncRNAs are regulated. Herein, we firstly revealed that overexpression of lncRNA-CR33942 could strengthen the expression of Imd pathway antimicrobial peptides Diptericin (Dpt) and Attacin-A (AttA) after infection, and vice versa. Secondly, RNA-seq analysis of post-infected lncRNA-CR33942-overexpressing flies further confirmed that lncRNA-CR33942 positively regulates the Drosophila Imd pathway. Mechanistically, we indicated that lncRNA-CR33942 interacts with NF-κB transcription factor Relish to promote its binding to Dpt and AttA promoters, thereby facilitating Dpt and AttA expression. Interestingly, we found that Relish can also directly promote lncRNA-CR33942 transcription by binding to its promoter. Finally, rescue experiments and dynamic expression profiling post-infection demonstrated the vital role of the Relish/lncRNA-CR33942/AMPs regulatory axis in enhancing inadequate Imd immune responses and maintaining immune homeostasis. Taken together, our study not only elucidates a novel mechanism about lncRNA in Drosophila Imd immune regulation, but also has important guiding significance for elucidating the complex regulatory mechanism of animal innate immune response.
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Project description:Thymic central tolerance is essential to preventing autoimmunity. In medullary thymic epithelial cells (mTECs), the Autoimmune regulator (Aire) gene plays an essential role in this process by driving the expression of a diverse set of tissue-specific antigens (TSAs), which are presented and help tolerize self-reactive thymocytes. Interestingly, Aire has a highly tissue-restricted pattern of expression, with only mTECs and peripheral extrathymic Aire-expressing cells (eTACs) known to express detectable levels in adults. Despite this high level of tissue specificity, the cis-regulatory elements that control Aire expression have remained obscure. We used sequence conservation analysis and ChIP-seq against the enhancer-associated histone mark H3K27ac to identify a candidate Aire cis-regulatory element. There is enrichment of H3K27ac near this element, ACNS1, in mTECs and the element also has characteristics of being NF-κB-responsive. Finally, we find that this element is essential for Aire expression in vivo and necessary to prevent spontaneous autoimmunity, reflecting the importance of this regulatory DNA element in promoting immune tolerance.
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Project description:Presentation of tissue-restricted antigens (TRA) in the thymus is essentialfor establishing self-tolerancethrough elimination of autoreactive Tcells.It remains unclear why certain self T cells can bypassthymic selectionand become driversoftissue-specific autoimmunity. Herewe assessedthymic TRA presented by a major histocompatibility class II molecule (MHC-II) that confers genetic propensity to develop type 1 diabetes. This analysisestablished the thymic peptidome containing self-peptidesderivedfrom variousperipheral tissues,butalso revealed a disparity in the MHC-II epitoperepertoirebetween thymus and the target site of autoimmunity, the pancreatic islets.The thymic repertoire consistedof canonicalMHC-IIepitopes capable of enforcing central tolerance but lacked presentation of uniqueepitopes derived from unconventionalself-proteinprocessing orneoepitopes formed by post-translational modifications. Suchepitopes were noteworthily generatedin the isletsvia a tissue-intrinsic mechanism, crinophagy, and were recognized by CD4 T cells escaping central tolerance.These findings supportthat central tolerance mechanisms are effective but incomplete, as tissue-characteristic handling of self-antigens may broaden the peripheralrepertoire thatextends beyond the scope of thymic selection.
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