TCA metabolism regulates DNA hypermethylation in LPS and Mycobacterium tuberculosis–induced immune tolerance
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE276988 | GEO | 2024/09/12
REPOSITORIES: GEO
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Project description:Severe and chronic infections, including pneumonia, sepsis, and tuberculosis (TB), induce long-lasting epigenetic changes that are associated with an increase in all cause post-infectious morbidity and mortality. We show that TCA cycle also regulates epigenetics, specifically DNA methylation, after infection induced immune tolerance. This data from TB patients who received everolimus with standard of care antibiotics, and have less DNA hypermethylation demonstrating proof of concept that metabolic manipulation can mitigate epigenetic scars.
2024-09-12 | GSE277003 | GEO
Project description:Remodeling of the tricarboxylic acid (TCA) cycle is a metabolic adaptation mechanism accompanying inflammatory macrophage activation. During this process, endogenous metabolites can adopt regulatory roles that govern specific aspects of inflammatory response, as recently shown for succinate, which regulates the downstream pro-inflammatory IL-1β-HIF1a axis. Itaconate is one of the most highly induced metabolites in activated macrophages, yet its functional significance remains unknown. Here, we show that itaconate modulates macrophage metabolism and effector functions via its effect on succinate dehydrogenase, by inhibiting conversion of succinate to fumarate. Through this action, itaconate exerts anti-inflammatory effects when administered in vitro and in vivo during macrophage activation and ischemia-reperfusion injury. Using newly generated Irg1-/- mice, which lack the ability to produce itaconate, we show that endogenous itaconate regulates succinate levels and function, changes in mitochondrial respiration, and inflammatory cytokine production during macrophage activation. These studies highlight itaconate as a major physiological regulator of the global metabolic rewiring and effector functions of inflammatory macrophages. Experiment 1: mature WT BMDM were treated for 12h with 0.25 mM dimethyl itaconate (DI) or vehicle (Unst) and then stimulated with LPS (E. coli 0111:B4; 100 ng/ml, 4h) (DI+LPS; LPS); Experiment 2: mature Irg1-/- BMDM were stimulated with LPS (E. coli 0111:B4; 100 ng/ml) and murine recombinant IFNg (50 ng/ml) for 24h.
2016-07-01 | E-GEOD-82043 | biostudies-arrayexpress
Project description:Remodeling of the tricarboxylic acid (TCA) cycle is a metabolic adaptation mechanism accompanying inflammatory macrophage activation. During this process, endogenous metabolites can adopt regulatory roles that govern specific aspects of inflammatory response, as recently shown for succinate, which regulates the downstream pro-inflammatory IL-1β-HIF1a axis. Itaconate is one of the most highly induced metabolites in activated macrophages, yet its functional significance remains unknown. Here, we show that itaconate modulates macrophage metabolism and effector functions via its effect on succinate dehydrogenase, by inhibiting conversion of succinate to fumarate. Through this action, itaconate exerts anti-inflammatory effects when administered in vitro and in vivo during macrophage activation and ischemia-reperfusion injury. Using newly generated Irg1-/- mice, which lack the ability to produce itaconate, we show that endogenous itaconate regulates succinate levels and function, changes in mitochondrial respiration, and inflammatory cytokine production during macrophage activation. These studies highlight itaconate as a major physiological regulator of the global metabolic rewiring and effector functions of inflammatory macrophages.
2016-07-01 | GSE82043 | GEO
Project description:Activation of macrophages by inflammatory stimuli leads to reprogramming of mitochondrial metabolism to support the production of pro-inflammatory cytokines. Hallmarks of this metabolic rewiring are downregulation of α-ketoglutarate formation via isocitrate dehydrogenase (IDH) and accumulation of glutamine-derived succinate, which enhances the inflammatory response via the activity of succinate dehydrogenase (SDH). Here, we identify the nuclear receptor Nur77 (Nr4a1) as a key regulator of the pro-inflammatory metabolic switch in macrophages. Nur77-deficient macrophages fail to downregulate IDH expression and accumulate higher levels of succinate and other downstream TCA cycle metabolites in response to an inflammatory stimulus. Consequently, these macrophages produce more nitric oxide and pro-inflammatory cytokines in an SDH-dependent manner. In vivo, bone marrow Nur77 deficiency exacerbates atherosclerosis development and leads to increased systemic succinate levels. In conclusion, Nur77 supports an anti-inflammatory metabolic state in macrophages that protects against chronic inflammatory diseases such as atherosclerosis.
2018-08-21 | GSE102359 | GEO
Project description:Activation of macrophages by inflammatory stimuli leads to reprogramming of mitochondrial metabolism to support the production of pro-inflammatory cytokines. Hallmarks of this metabolic rewiring are downregulation of α-ketoglutarate formation via isocitrate dehydrogenase (IDH) and accumulation of glutamine-derived succinate, which enhances the inflammatory response via the activity of succinate dehydrogenase (SDH). Here, we identify the nuclear receptor Nur77 (Nr4a1) as a key regulator of the pro-inflammatory metabolic switch in macrophages. Nur77-deficient macrophages fail to downregulate IDH expression and accumulate higher levels of succinate and other downstream TCA cycle metabolites in response to an inflammatory stimulus. Consequently, these macrophages produce more nitric oxide and pro-inflammatory cytokines in an SDH-dependent manner. In vivo, bone marrow Nur77 deficiency exacerbates atherosclerosis development and leads to increased systemic succinate levels. In conclusion, Nur77 supports an anti-inflammatory metabolic state in macrophages that protects against chronic inflammatory diseases such as atherosclerosis.
2018-08-21 | GSE102393 | GEO
Project description:Malic enzymes decarboxylate the tricarboxylic acid (TCA) cycle intermediate malate to the glycolytic end-product pyruvate and are well positioned to regulate metabolic flux in central carbon metabolism. The bacterium Sinorhizobium meliloti has a NAD(P)-malic enzyme (DME) and a NADP-malic enzyme (TME) and DME is required for symbiotic N2-fixation. To help understand the role of these enzymes, we examined growth, metabolic and transcriptional consequences resulting from the deletion of these enzymes. Few effects were observed upon growth with glucose, whereas growth with the gluconeogenic substrate, succinate, resulted in transcriptional and metabolic effects particularly in the dme mutant strains. When grown with succinate, DME mutant cells accumulated hexose sugar phosphates and trehalose, while TME mutants accumulated putrescine. Succinate-grown DME mutant cells also showed increased transcription of genes for gluconeogenesis and for pathways such as amino acid and fatty acid synthesis that divert metabolites away from the TCA cycle. These data suggested that, DME is required to regulate the levels of TCA cycle intermediates and that the activity of TME is insufficient to prevent the accumulation of TCA cycle intermediates in cells utilizing succinate as carbon source. Consistent with this, in short-1-3 hour incubations with succinate, dme mutant cells excreted large amounts of malate whereas little malate was excreted from tme or wild-type cells. These results support the suggestion that DME is required for N2-fixation in alfalfa because it is required for synthesis of pyruvate and acetyl-CoA and the rapid metabolism of C4-dicarboxylates supplied by the plant. RNA expression was measured for S. meliloti in exponential phase grown in MOPS (morpholinpropanesulfonic acid) buffered minimal media under 2 growth conditions: 1) 15 mM succinate, 2) 15 mM glucose; using wild type cells as well as dme and tme mutant strains (6 experiments, 2 replicates: total 12 samples)
2015-07-25 | E-GEOD-71308 | biostudies-arrayexpress
Project description:Classical stimulation of macrophages (MLPS/IFNγ) elicits the expression of inducible nitric oxide synthase (iNOS), generating large amounts of nitric oxide (NO) and inhibiting respiration. Consequent upregulation of glycolysis and a disrupted tricarboxylic acid (TCA) cycle underpin this switch to a pro-inflammatory phenotype. Here we show that the NOS cofactor tetrahydrobiopterin (BH4) modulates key aspects of metabolic remodelling in activated bone-marrow-derived macrophages (BMDMs) via NO production. Using two complementary mouse models that each lack the capacity for inducible NO generation, through different mechanisms, we reveal that NO regulates macrophage respiratory function via changes in the abundance of critical N-module subunits in Complex I, by HIF1α-mediated glycolytic remodelling, and by modulating levels of the critical TCA cycle metabolites, and inflammatory mediators, citrate, succinate, and itaconate. Taken together, our findings reveal new critical roles for iNOS-derived NO that are required for metabolic remodelling and cytokine production in macrophage inflammatory responses.
2019-05-31 | PXD010628 | Pride
Project description:In this report, we show that both glucose and glutamine are essential during OC differentiation, and both contribute to the maintenance of the TCA cycle. Early differentiation is associated with a broken TCA cycle, with IRG1 siphoning TCA intermediates for the production of itaconate, which accumulates extracellularly, stimulating the function of osteoblasts in vitro an in vivo and in vivo and is necessary to retain bone mass in mice.
2024-07-14 | GSE208359 | GEO
Project description:New antimalarial drugs are urgently needed to control drug resistant forms of the malaria parasite, Plasmodium falciparum. Although mitochondrial metabolism is the target of both existing drugs and new lead compounds, the role of the mitochondrial tricarboxylic acid (TCA) cycle remains poorly understood. Herein, we describe 11 genetic knockout parasite lines that delete six of the eight TCA cycle enzymes. Although all TCA knockouts grew normally in asexual blood stages, these metabolic deficiencies halted lifecycle progression in later stages. Specifically, aconitase knockout parasites arrested as late gametocytes, whereas α-ketoglutarate dehydrogenase deficient parasites failed to develop oocysts in the mosquitoes. Mass-spectrometry analysis of 13C isotope-labeled TCA mutant parasites showed that P. falciparum has significant flexibility in TCA metabolism. This flexibility manifested itself through changes in pathway fluxes and through altered exchange of substrates between cytosolic and mitochondrial pools. Our findings suggest that mitochondrial metabolic plasticity is essential for parasite development . Two parallel timecourses resulting in a total of 16 samples (8 wildtype, Isocitrate Dehydrogenase/alpha-Ketogluterate Dehydrogenase double knockout) were hybridized against a Cy3-labeled reference pool of 3D7 mixed stage parasites on a two-color array.
2014-08-01 | E-GEOD-59015 | biostudies-arrayexpress
Project description:ACOD1 is the enzyme repurposing cisaconitate from the tricarboxylic acid (TCA) cycle in the mitochondria to produce itaconate, a metabolite with anti-inflammatory and tolerogenic functions. In particular, itaconate accumulation in macrophages is known to oppose pro-inflammatory cytokine production mainly by inhibiting succinate dehydrogenase activity, activating the NRF2 and ATF3driven responses and inhibiting NLRP3. Itaconate biosynthesis was found to be induced in the liver of mice exposed to ischemia reperfusion (I/R) stress and to oppose the resulting tissue injury by sustaining hepatoprotective antioxidant programs. Whether ACOD1 plays a role in the homeostatic response of liver to different noninfectious injuring conditions remains largely unexplored. This study investigates the contribution of itaconate biosynthesis in the response of liver to dietary lipid overload and in the development of associated nonalcoholic fatty liver disease.
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