Itaconate suppresses atherosclerosis by impeding inflammation through Nrf2 signaling
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE235749 | GEO | 2024/02/14
REPOSITORIES: GEO
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Project description:RNA-sequencing demonstrated Acod1 (Aconitate decarboxylase 1) as one of the top genes induced by air polution particulate matter (PM) in macrophages. We therefore sought to determine the effect of both exogenous itaconate (4-octyl itaconate) and endogenous itaconate on PM-induced inflammation in macrophages through RNA sequencing.
2020-04-07 | GSE143881 | GEO
Project description:The Krebs cycle enzyme Aconitate Decarboxylase 1 (ACOD1) mediates itaconate synthesis in monocytes and macrophages. Here, we explore the role of endogenous ACOD1-itaconate pathway in the activation of BMDM after imiquimod treatment.
2024-04-17 | GSE250384 | GEO
Project description:Immune-response gene 1 (IRG1) transcription is rapidly induced by pathogen infections and inflammatory conditions primarily in cells of myeloid lineage. Deletion of Irg1 in mice causes severe defects in response to bacterial and viral infection and rapid death. IRG1 encodes a mitochondrial metabolic enzyme, aconitate decarboxylase 1 (ACOD1), that catalyzes the decarboxylation of cis-aconitate, a tricarboxylic acid cycle intermediate, to produce the anti-inflammatory metabolite itaconic acid (ITA). ITA can inhibit SDH5, resulting in elevated levels of succinate and metabolic reprogramming, or alkylate protein cysteine residues to induce electrophilic stress response mediated by NRF2 and IκBζ. Here we show that ITA is an antagonist of α-ketoglutarate (α-KG) and a potent inhibitor of α-KG/Fe2+-dependent TET family of DNA dioxygenases. In vitro, ITA binds to TET2 and inhibits the catalytic activity of TET2 and, reciprocally, α-KG blocks ITA binding to and inhibition of TET2. In vivo, lipopolysaccharides (LPS) treatment, which induces IRG1 expression and causes the intracellular accumulation of ITA, inhibits TET activity in Irg1-WT, but not Irg1-KO macrophages. Moreover, TET2 is a major target of ITA function in suppressing LPS-induced genes. LPS stimulates p65 NF-κB/RelA to bind with and recruit TET2 to hydroxymethylate and activate the Nfkbiz gene, which encodes IκBζ. Our results thus identify a physiological metabolite inhibitor of TET enzymes and reveal a novel mechanism for the anti-inflammatory function of ITA through dampening TET2-mediated NF-κB signaling.
2022-01-10 | GSE158580 | GEO
Project description:One primary metabolic manifestation of inflammation is the diversion of cis-aconitate within the tricarboxylic acid (TCA) cycle to synthesize the immunometabolite itaconate. Itaconate is well established to possess immunomodulatory and metabolic effects within myeloid cells and lymphocytes, however, its effects in other organ systems during sepsis remain less clear. Utilizing Irg1 knockout mice that are deficient in synthesizing itaconate, we aimed at understanding the metabolic role of itaconate in the liver and systemically during sepsis. We find itaconate aids in lipid metabolism during sepsis. Specifically, Irg1 KO mice develop a heightened level of hepatic steatosis when induced with polymicrobial sepsis. Proteomics analysis reveal enhanced expression of enzymes involved in fatty acid oxidation in following 4-ocytl itaconate (4-OI) treatment in vitro. Downstream analysis reveals itaconate stabilizes the expression of the mitochondrial fatty acid uptake enzyme CPT1a, mediated by its hypoubiquitination. Chemoproteomic analysis revealed itaconate interacts with proteins involved in protein ubiquitination as a potential mechanism underlying its stabilizing effect on CPT1a. From a systemic perspective, we find itaconate deficiency triggers a hypothermic response following endotoxin stimulation, potentially mediated by brown adipose tissue (BAT) dysfunction. Finally, by use of metabolic cage studies, we demonstrate Irg1 KO mice rely more heavily on carbohydrates versus fatty acid sources for systemic fuel utilization in response to endotoxin treatment. Our data reveal a novel metabolic role of itaconate in modulating fatty acid oxidation during polymicrobial sepsis.
2024-01-29 | PXD047706 | Pride
Project description:Neutrophils are critical in the host defense against Staphylococcus aureus, a major human pathogen. However, even in the setting of a robust neutrophil response, S. aureus can cause persistent infection. Here we demonstrate that S. aureus impairs neutrophil function by triggering the production of the anti-inflammatory metabolite, itaconate. The enzyme that synthesizes itaconate, Irg1, is selectively expressed in neutrophils during S. aureus pneumonia. Itaconate inhibits neutrophil glycolysis and oxidative burst, which impairs survival and bacterial killing. In a murine pneumonia model, neutrophil Irg1 expression protects critical lung cell populations from oxidative stress but compromises bacterial clearance. S. aureus is thus able to evade innate immune clearance by targeting neutrophil metabolism and inducing the production of the antiinflammatory metabolite itaconate.
2023-01-01 | GSE215195 | GEO
Project description:The tumor microenvironment possesses multiple overlapping mechanisms that suppress anti-tumor immunity. Itaconate is a metabolite produced from the Krebs cycle intermediate cis-aconitate by the activity of immune-responsive gene 1 (IRG1). While it is known to be immune modulatory, the role of itaconate in anti-tumor immunity is unclear. Here, we demonstrate that myeloid-derived suppressor cells (MDSCs) secreted itaconate that can be taken up by CD8+ T cells and suppress their proliferation, cytokine production, and cytolytic activity. Metabolite profiling, stable-isotope tracing and metabolite supplementation studies indicated that itaconate suppressed biosynthesis of aspartate and serine/glycine in CD8+ T cells to attenuate their proliferation. Moreover, stromal deletion of IRG1 in mice bearing allografted tumors resulted in decreased tumor growth, inhibited the immune suppressive activities of MDSCs, reduced levels of itaconate in tumors, promoted anti-tumor immunity of CD8+ T cells, and enhanced the anti-tumor activity of anti-PD-1 antibody treatment. Importantly, we found a significant negative correlation between IRG1 expression and response to PD-1 immune checkpoint blockade in melanoma patients. Our findings not only reveal a previously unknown role of itaconate as an immune checkpoint metabolite secreted from MDSCs to suppress CD8+ T cells, but also establish IRG1 as a novel myeloid-selective target in immunometabolism to promote anti-tumor immunity and enhance the efficacy of immune checkpoint protein blockade.
2022-11-15 | GSE190028 | GEO
Project description:Brucellosis is one of the most widespread bacterial zoonoses worldwide. Here, our aim was to identify the effector mechanisms controlling the early stages of intranasal infection with Brucella in C57BL/6 mice. During the first 48 hours of infection, alveolar macrophages (AMs) are the main cells infected in the lungs. Using RNA sequencing, we identified the aconitate decarboxylase 1 gene (Acod1; also known as Immune responsive gene 1), as one of the genes most upregulated in murine AMs in response to B. melitensis infection at 24 hours post-infection. Upregulation of Acod1 was confirmed by RT-qPCR in lungs infected with B. melitensis and B. abortus. We observed that Acod1-/- C57BL/6 mice display a higher bacterial load in their lungs than wild-type (wt) mice following B. melitensis or B. abortus infection, demonstrating that Acod1 participates in the control of pulmonary Brucella infection. The ACOD1 enzyme is mostly produced in mitochondria of macrophages, and converts cis-aconitate, a metabolite in the Krebs cycle, into itaconate. Dimethyl itaconate (DMI), a chemically-modified membrane permeable form of itaconate, has a dose-dependent inhibitory effect on Brucella growth in vitro. Interestingly, modelling studies suggest the binding of itaconate into the binding site of isocitrate lyase. DMI does not inhibit multiplication of the isocitrate lyase deletion mutant ∆aceA B. abortus in vitro. Finally, we observed that, unlike the wt strain, the ∆aceA B. abortus strain multiplies similarly in wt and Acod1-/- C57BL/6 mice. These data suggest that bacterial isocitrate lyase might be a target of itaconate in AMs.
2021-09-21 | GSE180699 | GEO
Project description:Aconitate decarboxylase 1 (ACOD1) is the enzyme synthesizing itaconate, an immuno-regulatory metabolite tuning host-pathogen interactions. Such functions are achieved by affecting metabolic pathways regulating inflammation and microbe survival. However, at the whole-body level, metabolic roles of itaconate remain largely unresolved. By using multiomics-integrated approaches, here we show that ACOD1 responds to high-fat diet consumption in mice by promoting gut microbiota alterations supporting metabolic disease. Genetic disruption of itaconate biosynthesis protects mice against obesity, alterations in glucose homeostasis and liver metabolic dysfunctions by decreasing meta-inflammatory responses to dietary lipid overload. Mechanistically, fecal metagenomics and microbiota transplantation experiments demonstrate such effects are dependent on an amelioration of the intestinal ecosystem composition, skewed by high-fat diet feeding towards obesogenic phenotype. In particular, unbiased fecal microbiota profiling and axenic culture experiments point towards a primary role for itaconate in inhibiting growth of Bacteroidaceae and Bacteroides, family and genus of Bacteroidetes phylum, the major gut microbial taxon associated with metabolic health. Specularly to the effects imposed by Acod1 deficiency on fecal microbiota, oral itaconate consumption enhances diet-induced gut dysbiosis and associated obesogenic responses in mice. Unveiling an unrecognized role of itaconate, either endogenously produced or exogenously administered, in supporting microbiota alterations underlying diet-induced obesity in mice, our study points ACOD1 as a target against inflammatory consequences of overnutrition.
2024-02-05 | GSE213632 | 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:Lung metastasis is the principal cause of breast cancer-related mortality. Neutrophils have emerged as an important component of the tumor microenvironment (TME), supporting tumor proliferation and mediating immunosuppression. Here, we show that aconitate decarboxylase 1 (Acod1) is highly expressed in tumor-infiltrating neutrophils and promotes breast cancer lung metastasis by supporting neutrophil survival in the TME. Acod1 expression is regulated by tumor-derived granulocyte-macrophage colony-stimulating factor (GM-CSF) through the JAK/STAT signaling pathway and CCAAT/enhancer-binding protein beta (C/EBPβ) transcription factor activity. Acod1 loss in tumor-infiltrating neutrophils leads to ferroptosis-like cell death, resulting in decreased frequency of neutrophils in the TME. Mechanistically, itaconate, the product of Acod1, activates nuclear factor erythroid 2-related factor 2 (Nrf2), resulting in upregulated antioxidant responses and decreased lipid-reactive oxygen species. Genetical deletion of Acod1 in neutrophils suppresses lung metastasis of breast cancer in mouse models by decreasing neutrophil-lymphocyte ratio and elevating cytotoxic T cell response. Importantly, genetic targeting of Acod1 enhances the anti-tumor efficacy of immune checkpoint blockade. Overall, our findings reveal a mechanism of how immunosuppressive neutrophils survive in the harsh TME and support Acod1-targeting approaches for cancer treatment.
2023-09-13 | GSE216425 | GEO