Itaconate mediates an immunometabolic crosstalk between osteoclasts and osteoblasts
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE208359 | GEO | 2024/07/14
REPOSITORIES: GEO
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Project description:Bone remodeling is a highly dynamic process dependent on the precise coordination of osteoblasts and hematopoietic-cell derived osteoclasts. Emerging evidence indicates that cellular differentiation is associated with a metabolic rewiring in conjunction with the acquisition of specific effector functions. Changes in core metabolic pathways during osteoclastogenesis, however, are largely unexplored and it is unknown whether and how these processes are involved in bone homeostasis. We show that during differentiation preosteoclasts rearrange their tricarboxylic acid (TCA) cycle, a process crucially depending on both glucose and glutamine. This rearrangement is characterized by induction of immunoresponsive gene 1 (Irg1) and production of itaconate, which accumulates intra- and extracellularly. While the IRG1-itaconate axis is dispensable for osteoclast generationin vitroandin vivo, we demonstrate that itaconate stimulates osteoblasts by accelerating osteogenic differentiation, reducing proliferation and shifting ATP production from mitochondrial respiration to glycolysis. Additionally, supplementation of itaconate increases bone formation by boosting osteoblast activity in mice. Conversely,Irg1deficient mice exhibit decreased bone mass and have reduced osteoproliferative lesions in experimental arthritis. In summary, we identify itaconate, generated as a result of the metabolic rewiring during osteoclast differentiation, as a previously unrecognized regulator of the crosstalk between osteoclasts and osteoblasts
2024-07-24 | GSE236452 | 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: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: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: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: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:Itaconate has emerged as a critical immunoregulatory metabolite. Here, we examined the therapeutic potential of itaconate in atherosclerosis. We found that both itaconate and the enzyme that synthesizes it, aconitate decarboxylase 1 (Acod1, also known as “immune-responsive gene 1”/IRG1) are upregulated during atherogenesis in mice. Here we analzyed the anatomy of atherosclerotic plaques from wildtype and Acod1-/- mice through single cell RNA-seq.
2024-02-14 | GSE235749 | GEO
Project description:Itaconate is a metabolite naturally produced in large amounts in macrophages after exposure to immune stimulation. Following the discovery of itaconate’s immunoregulatory properties, several ester derivatives of this dicarboxylic acid were designed to further examine its role. We evaluated the metabolic, electrophilic, and immunologic profiles of macrophages treated with unmodified itaconate and a panel of itaconate derivatives. We found that only unmodified itaconate strongly enhances LPS-induced IFNb secretion after 12h pre-treatment. Thus, we compared the transcriptional profile of wild type and Irg1-/- cells, which are unable to produce itaconate, after 24h LPS stimulation. We find that cells lacking itaconate have impaired downstream type I interferon signaling, and that addition of itaconate Irg1-/- BMDMs restores this signaling back to levels comparable to wild type. This data highlights the role of itaconate as an immunoregulatory metabolite, and highlights the importance of using unmodified itaconate or genetic knockout models in future mechanistic studies.
2020-05-15 | GSE145950 | GEO
Project description:Atherosclerosis is the major underlying cause of cardiovascular disease (CVD) mortality and is fueled by a failure to resolve inflammation within the vessel wall1. The mechanisms underpinning sustained inflammation within this microenvironment are not fully elucidated. A more comprehensive understanding of the immunoregulatory pathways modulating inflammation in this context holds the potential to inform the development of more specific therapies. Immune responsive gene 1 (Irg1) is an enzyme that diverts cis-aconitate from the TCA cycle and produces the metabolite itaconate, which elicits immunological tolerance in the context of microbial infection2–4. We hypothesized that the IRG1-itaconate axis restricts inflammation in the atherosclerotic plaque.
2024-03-19 | GSE252241 | GEO
Project description:Atherosclerosis is the major underlying cause of cardiovascular disease (CVD) mortality and is fueled by a failure to resolve inflammation within the vessel wall1. The mechanisms underpinning sustained inflammation within this microenvironment are not fully elucidated. A more comprehensive understanding of the immunoregulatory pathways modulating inflammation in this context holds the potential to inform the development of more specific therapies. Immune responsive gene 1 (Irg1) is an enzyme that diverts cis-aconitate from the TCA cycle and produces the metabolite itaconate, which elicits immunological tolerance in the context of microbial infection2–4. We hypothesized that the IRG1-itaconate axis restricts inflammation in the atherosclerotic plaque.
2024-03-19 | GSE253555 | GEO