Non-oxidative pentose phosphate pathway controls regulatory T cell function by integrating metabolism and epigenetics
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE198995 | GEO | 2022/03/31
REPOSITORIES: GEO
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Project description:Non-oxidative pentose phosphate pathway (PPP) is a crucial gatekeeper of glucose catabolism in metabolic tissues. However, its role in regulatory T cells (Tregs) remains unknown. Here we report deleting transketolase (TKT), an indispensable enzyme of non-oxidative PPP, in Tregs caused a fatal auto-immune disease in mice. TKT deletion impaired suppressive capability without disturbing Treg cell number. Mechanistically, TKT deficiency caused Treg metabolic remodeling with decreased glucose catabolism, activated fatty acid and amino acid catabolism and uncontrolled oxidative phosphorylation. Moreover, excessive ammonia from deregulated amino acid catabolism impaired mitochondrial fitness while reduced α-ketoglutarate/succinate ratio led to DNA hypermethylation, limiting functional gene expression and suppressive activity of TKT-deficient Tregs. Therefore, our study identifies non-oxidative PPP as a new pathway for controlling Treg function.
2022-03-31 | GSE172047 | GEO
Project description:Non-oxidative pentose phosphate pathway (PPP) is a crucial gatekeeper of glucose catabolism in metabolic tissues. However, its role in regulatory T cells (Tregs) remains unknown. Here we report deleting transketolase (TKT), an indispensable enzyme of non-oxidative PPP, in Tregs caused a fatal auto-immune disease in mice. TKT deletion impaired suppressive capability without disturbing Treg cell number. Mechanistically, TKT deficiency caused Treg metabolic remodeling with decreased glucose catabolism, activated fatty acid and amino acid catabolism and uncontrolled oxidative phosphorylation. Moreover, excessive ammonia from deregulated amino acid catabolism impaired mitochondrial fitness while reduced α-ketoglutarate/succinate ratio led to DNA hypermethylation, limiting functional gene expression and suppressive activity of TKT-deficient Tregs. Therefore, our study identifies non-oxidative PPP as a new pathway for controlling Treg function.
2022-03-31 | GSE171675 | GEO
Project description:The Pentose Phosphate Pathway (PPP), a metabolic offshoot of the glycolytic pathway, provides protective metabolites and molecules essential for cell redox balance and survival. Transketolase (TKT) is the critical enzyme that controls the extent of “traffic flow” through the PPP. Here, we explored the role of TKT in maintaining the health of the human retina. We found that Müller cells were the primary retinal cell type expressing TKT in the human retina. We further explored the role of TKT in human Müller cells by knocking down its expression in primary cultured Müller cells (huPMCs), isolated from the human retina (11 human donors in total), under lightinduced oxidative stress. TKT knockdown and light stress reduced TKT enzymatic activities and the overall metabolic activities of huPMCs with no detectable cell death. TKT knockdown restrained the PPP traffic flow, reduced the expression of NAD(P)H Quinone Dehydrogenase 1 (NQO1) and impaired the antioxidative response of NRF2 to light stress. TKT knockdown also inhibited overall glucose intake, reduced expression of Dihydrolipoamide dehydrogenase (DLD) and impaired the energy supply of huPMCs. In summary, Müller cell-mediated TKT activity plays a critical protective role in the stressed retina. Knockdown of TKT disrupted the PPP and impaired overall glucose utilisation by huPMCs and rendered huPMCs more vulnerable to light stress by impairing energy supply and antioxidative NRF2 responses.
2022-06-26 | GSE198554 | GEO
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)
2010-12-22 | 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)
2010-12-22 | BIOMD0000000289 | BioModels
Project description:The therapeutic use of regulatory T cells (Tregs) in patients with autoimmune disorders has been hampered by the biological variability of memory Treg populations in the peripheral blood. In this study, we reveal through a combination of quantitative proteomic, multiparametric flow cytometry, RNA-seq data analysis and functional assays, that CD49f is heterogeneously expressed among human Tregs and impacts their immunomodulatory function. High expression of CD49f defines a subset of dysfunctional Tregs in the human blood characterized by a Th17-like phenotype and impaired suppressive capacity. CD49f is similarly distributed between naïve and memory Tregs and impacts the expression of CD39, CTLA-4, FoxP3 and CCR6 specifically in the memory compartment. Accumulation of CD49f high memory Tregs in the blood of ulcerative colitis patients correlates with disease severity. Our results highlight important considerations for Treg immunotherapy design in patients with inflammatory bowel disease which could possibly extend to other autoimmune disorders.
2021-08-06 | PXD022095 | Pride
Project description:Foxp3+ T-regulatory (Treg) cells maintain immune homeostasis and limit autoimmunity, but can also curtail host responses to cancers. Tregs are therefore promising targets to enhance anti-tumor immunity. Histone/protein acetyltransferases (HATs) promote chromatin accessibility, gene transcription and the function of multiple transcription factors and non-histone proteins. We found that conditional deletion or pharmacologic inhibition of one specific HAT, p300, in Foxp3+ Tregs, increased TCR-induced apoptosis in Tregs, impaired Treg suppressive function and iTreg peripheral conversion, and limited tumor growth in immunocompetent, but not in immunodeficient, hosts. Our data demonstrate that p300 is important for Foxp3+ Treg function and homeostasis in vivo and in vitro, and identify a novel mechanism to diminish Treg function without overtly impairing effector Tcell responses or inducing autoimmunity. Collectively, these data suggest a new approach for cancer immunotherapy. RNA from three independent samples from magnetically separated CD4+CD25+ Treg of fl-p300/Foxp3cre mice, compared to wild type (Foxp3cre) control (all C57Bl/6 background).
2013-08-18 | E-GEOD-47989 | biostudies-arrayexpress
Project description:The proposed use of Foxp3+ T-regulatory (Treg) cells as potential cellular therapy in patients with autoimmune diseases, or post-hemopoietic stem cell or organ transplantation, requires a sound understanding of the transcriptional regulation of Foxp3 expression. Conserved CpG dinucleotides in the Treg-specific demethylated region (TSDR) upstream of Foxp3 are demethylated only in stable, thymic-derived Foxp3+ Tregs. Since methyl-binding domain (Mbd) proteins recruit histone-modifying and chromatin-remodeling complexes to methylated sites, we tested whether targeting of Mbd2 might promote demethylation of Foxp3 and thereby promote Treg numbers or function. Surprisingly, while ChIP analysis showed Mbd2 binding to the Foxp3-associated TSDR site in Tregs, Mbd2 targeting by homologous recombination or siRNA decreased Treg numbers and impaired Treg suppressive function in vitro and in vivo. Moreover, we found complete TSDR demethylation in WT Tregs but >75% methylation in Mbd2-/- Tregs, whereas re-introduction of Mbd2 into Mbd2-null Tregs restored TSDR demethylation, Foxp3 gene expression and Treg suppressive function. Lastly, Mbd2-/- Tregs had markedly binding of the DNA demethylase enzyme, Tet2, in the TSDR region. These data show that Mbd2 has a key role in promoting TSDR demethylation, Foxp3 expression and Treg suppressive function. RNA from three independent samples from magnetically separated CD4+CD25+ Treg of MBD2–/– mice, compared to wild type control (all Balb/c background).
2013-09-01 | E-GEOD-48653 | biostudies-arrayexpress
Project description:Tregs play a fundamental role in immune tolerance via control of self-reactive effector T cells (Teffs). This function is dependent on maintenance of a high intracellular cAMP concentration. A number of microRNAs are implicated in the maintenance of Tregs. In this study, we demonstrate that peripheral immune tolerance is critically dependent on posttranscriptional repression of the cAMP-hydrolyzing enzyme phosphodiesterase-3b (Pde3b) by microRNA-142-5p (miR-142-5p). In this manner, miR-142-5p acts as an immunometabolic regulator of intracellular cAMP, controlling Treg suppressive function. Mir142 was associated with a super enhancer bound by the Treg lineage–determining transcription factor forkhead box P3 (FOXP3), and Treg-specific deletion of miR-142 in mice (TregΔ142) resulted in spontaneous, lethal, multisystem autoimmunity, despite preserved numbers of phenotypically normal Tregs. Pharmacological inhibition and genetic ablation of PDE3B prevented autoimmune disease and reversed the impaired suppressive function of Tregs in TregΔ142 animals. These findings reveal a critical molecular switch, specifying Treg function through the modulation of a highly conserved, cell-intrinsic metabolic pathway. Modulation of this pathway has direct relevance to the pathogenesis and treatment of autoimmunity and cancer.
2019-12-20 | GSE72279 | GEO
Project description:Foxp3+ T-regulatory cells (Tregs) are key to immune homeostasis such that their diminished numbers or function can cause autoimmunity and allograft rejection. Foxp3+ Tregs express histone/protein deacetylases (HDACs) that regulate chromatin remodeling, gene expression and protein function. Pan-HDAC inhibitors developed for oncology enhance Treg production and suppression but have limited non-oncologic applications given their broad effects. We show, using HDAC6-deficient mice and WT mice treated with HDAC6-specific inhibitors, that HDAC6 inhibition promotes Treg suppressive activity in models of inflammation and autoimmunity, including multiple forms of experimental colitis and fully MHC-incompatible cardiac allograft rejection. Many of the beneficial effects of HDAC6 targeting are also achieved by inhibition of the HDAC6-regulated protein, HSP90. Hence, selective targeting of a single HDAC isoform, HDAC6, or its downstream target, HSP90, can promote Treg-dependent suppression of autoimmunity and transplant rejection. RNA from three independent samples from magnetically separated CD4+CD25+ Treg of HDAC6 knock out, compared to wild type (C57BL6) control
2011-05-01 | E-GEOD-27896 | biostudies-arrayexpress