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:Itaconate mediates an immunometabolic crosstalk between osteoclasts and osteoblasts
| PRJNA859680 | ENA
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:Treatment with the toll-like receptor (TLR) 4 agonist monophosphoryl lipid A (MPLA) conditions innate immunocytes to respond robustly to subsequent infection, a phenotype termed innate immune memory. Our published studies show that metabolic reprogramming of macrophages is a prominent feature of the memory phenotype. We undertook studies to define the functional contributions of tricarboxylic acid (TCA) reprogramming to innate immune memory. We observed that MPLA potently induced expression of immunoresponsive gene 1 (Irg1) and accumulation of its byproduct, the TCA cycle metabolite itaconate, in macrophages. Treatment with MPLA enhanced microbial clearance in wild type (WT), but not Irg1-deficient, mice, demonstrating that itaconate contributes to the antimicrobial phenotype in vivo. Treatment with MPLA equally augmented innate leukocyte recruitment, phagocytosis, respiratory burst and cytokine responses in WT and Irg1-deficient innate leukocytes after infection. However, the ability of Irg1-deficient macrophages to kill Pseudomonas aeruginosa was impaired. We further observed that itaconate is directly antimicrobial against P. aeruginosa at pH 5, which is characteristic of the phagolysosome, and is facilitated by reactive oxygen species. RNA sequencing revealed suppressed transcription of genes associated with phagolysosome function in Irg1 deficient macrophages. This study identifies a contribution of itaconate to MPLA-induced augmentation of innate antimicrobial immunity via facilitation of microbial killing.
2024-10-09 | GSE278668 | GEO
Project description:To investigate the role of Irg1-itaconate or Hemin in macrophages, bone marrow-derived macrophages (BMDMs) from WT mice and Irg1 KO mice were extracted and cultured. After 7 days of cells culture, the BMDMs from WT mice were treated 120 μM 4-octyl itaconate (4-OI) for 15 h, 15 μM Hemin for 12 h, and the BMDMs from Irg1 KO mice and WT mice were treated Vehicle for 12 h. We then performed gene expression profiling analysis using data obtained from RNA-seq of 4-OI, Hemin or vehicle treated WT BMDMs and Irg1 KO BMDMs.
2024-06-28 | GSE221734 | 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