Project description:Upon antigen stimulation, the bioenergetic demands of T cells increase dramatically over the resting state. Although a role for the metabolic switch to glycolysis has been suggested to support increased anabolic activities and facilitate T cell growth and proliferation, whether cellular metabolism controls T cell lineage choices remains poorly understood. Here we report that the glycolytic pathway is actively regulated during the differentiation of inflammatory TH17 and Foxp3-expressing regulatory T cells (Treg), and controls cell fate determination. TH17 but not Treg-inducing conditions resulted in strong upregulation of the glycolytic activity and induction of glycolytic enzymes. Blocking glycolysis inhibited TH17 development while promoting Treg cell generation. Moreover, the transcription factor hypoxia-inducible factor 1a (HIF1a) was selectively expressed in TH17 cells and its induction required signaling through mTOR, a central regulator of cellular metabolism. HIF1a-dependent transcriptional program was important for mediating glycolytic activity, thereby contributing to the lineage choices between TH17 and Treg cells. Lack of HIF1a resulted in diminished TH17 development but enhanced Treg differentiation, and protected mice from autoimmune CNS inflammation. Our studies demonstrate that HIF1a-dependent glycolytic pathway orchestrates a metabolic checkpoint for the differentiation of TH17 and Treg cells. Naïve CD4 T cells from wild-type and HIF1a-deficient mice (in triplicates each group) were differentiated under TH17 conditions for 2.5 days, and RNA was analyzed by microarrays.
Project description:Upon antigen stimulation, the bioenergetic demands of T cells increase dramatically over the resting state. Although a role for the metabolic switch to glycolysis has been suggested to support increased anabolic activities and facilitate T cell growth and proliferation, whether cellular metabolism controls T cell lineage choices remains poorly understood. Here we report that the glycolytic pathway is actively regulated during the differentiation of inflammatory TH17 and Foxp3-expressing regulatory T cells (Treg), and controls cell fate determination. TH17 but not Treg-inducing conditions resulted in strong upregulation of the glycolytic activity and induction of glycolytic enzymes. Blocking glycolysis inhibited TH17 development while promoting Treg cell generation. Moreover, the transcription factor hypoxia-inducible factor 1a (HIF1a) was selectively expressed in TH17 cells and its induction required signaling through mTOR, a central regulator of cellular metabolism. HIF1a-dependent transcriptional program was important for mediating glycolytic activity, thereby contributing to the lineage choices between TH17 and Treg cells. Lack of HIF1a resulted in diminished TH17 development but enhanced Treg differentiation, and protected mice from autoimmune CNS inflammation. Our studies demonstrate that HIF1a-dependent glycolytic pathway orchestrates a metabolic checkpoint for the differentiation of TH17 and Treg cells.
Project description:T helper 17 (Th17) cells are a distinct subset of CD4+ T cells necessary for maintaining gut homeostasis and have prominent roles in autoimmunity and inflammation. Th17 cells have unique metabolic features, including a stem cell-like signature and reliance on mitochondrial respiratory chain function and tricarboxylic acid (TCA) cycle to coordinate metabolic and epigenetic remodeling. Dynamic changes in mitochondrial membrane morphology are key to sustain organelle function. However, it remains unclear whether mitochondrial membrane remodeling orchestrates metabolic and differentiation events in Th17 cells. Here we demonstrate that mitochondrial membrane fusion and tight cristae organization are required for Th17 cell function (i.e. cytokine expression). As a genetic model system we employ Th17 specific deletion of optic atrophy 1 (OPA1), a gene that encodes a protein involved in mitochondrial inner membrane fusion and cristae organization. As a result, we find that Th17 cells rely on mitochondrial fusion (due to their low metabolic activity). Here, we carry out DIA-based differential quantitative proteomic analysis of murine wild-type and OPA1 knock-out Th17 cells. Through Ingenuity pathway analysis and together with transcriptional and metabolomic profiling we identify the serine/threonine kinase liver associated kinase B1 (LKB1/STK11) as an essential node coupling mitochondrial function to IL-17A cytokine expression in T cells.
Project description:An imbalance of T helper (Th17) cells and regulatory T (Treg) cells contributes to the pathogenesis of autoimmune diseases. The endogenous metabolite itaconate (ITA) is a regulator of macrophages; however, its role in T cells regulation is unclear. Here, we show that ITA inhibited Th17 cell differentiation and promoted Treg cell differentiation via metabolic and epigenetic reprogramming. Mechanistically, ITA suppressed glycolysis and mitochondrial respiration in Th17 and Treg-polarizing T cells. In Th17 cells, the S-adenosyl-L-methionine/ S-adenosylhomocysteine ratio was decreased following ITA administration in vitro, subsequently altering the epigenetic status. Further, ITA inhibited RORγt binding at the Il17a promoter, resulting in reduced IL-17A expression. In Treg cells, ITA reduced 2-hydroxyglutarate levels, which suppressed Foxp3 expression. The adoptive transfer of ITA-treated Th17-polarizing T cells ameliorated experimental autoimmune encephalomyelitis. Collectively, these results indicate that ITA serves as a crucial metabolic regulator for Th17/Treg cell balance and a potential therapeutic agent against autoimmune diseases.
Project description:An imbalance of T helper (Th17) cells and regulatory T (Treg) cells contributes to the pathogenesis of autoimmune diseases. The endogenous metabolite itaconate (ITA) is a regulator of macrophages; however, its role in T cells regulation is unclear. Here, we show that ITA inhibited Th17 cell differentiation and promoted Treg cell differentiation via metabolic and epigenetic reprogramming. Mechanistically, ITA suppressed glycolysis and mitochondrial respiration in Th17 and Treg-polarizing T cells. In Th17 cells, the S-adenosyl-L-methionine/ S-adenosylhomocysteine ratio was decreased following ITA administration in vitro, subsequently altering the epigenetic status. Further, ITA inhibited RORγt binding at the Il17a promoter, resulting in reduced IL-17A expression. In Treg cells, ITA reduced 2-hydroxyglutarate levels, which suppressed Foxp3 expression. The adoptive transfer of ITA-treated Th17-polarizing T cells ameliorated experimental autoimmune encephalomyelitis. Collectively, these results indicate that ITA serves as a crucial metabolic regulator for Th17/Treg cell balance and a potential therapeutic agent against autoimmune diseases.
Project description:Tumor cells exhibit aberrant metabolism characterized by high glycolysis even in the presence of oxygen. This metabolic reprogramming, known as the Warburg effect, provides tumor cells with the substrates and redox potential required for the generation of biomass. Here, we show that the mitochondrial NAD-dependent deacetylase SIRT3 is a crucial regulator of the Warburg effect. SIRT3 loss promotes a metabolic profile consistent with high glycolysis required for anabolic processes in vivo and in vitro. Mechanistically, SIRT3 mediates metabolic reprogramming independently of mitochondrial oxidative metabolism and through HIF1a, a transcription factor that controls expression of key glycolytic enzymes. SIRT3 loss increases reactive oxygen species production, resulting in enhanced HIF1a stabilization. Strikingly, SIRT3 is deleted in 40% of human breast cancers, and its loss correlates with the upregulation of HIF1a target genes. Finally, we find that SIRT3 overexpression directly represses the Warburg effect in breast cancer cells. In sum, we identify SIRT3 as a regulator of HIF1a and a suppressor of the Warburg effect. RNA isolated from brown adipose tissue of SIRT3 WT and KO mice. 5 wild-type samples and 5 SIRT3 KO samples
Project description:IMV induces transcription of key glycolytic enzymes in alveolar epithelial type II mice IMV induced transcription of key glycolytic enzymes is HIF1A dependent
Project description:- transcription factor interferon regulatory factor 4 (IRF4) = crucial transcription factor for different immune cells, incl pro-inflammatory Th17 and anti-inflammatory Treg cells
- IRF4 is essential for the cell differentiation and fate determination
- however molecular mechanisms of IRF4-mediated gene expression in fully differentiated Th17/Treg cells are still not fully understood
- integration of data derived from affinity-purification and full mass spectrometry-based proteome analysis with chromatin immune precipitation sequencing (ChIP-Seq)
- characterization of proteins generally involved in the T cell development as well as subtype-specific differentiation and identification of novel, yet uncharted IRF4 interactors
Project description:While gene regulatory networks involved in cardiogenesis have been characterized, the role of bioenergetics remains less studied. Here we show that until midgestation, myocardial metabolism is compartmentalized, with a glycolytic signature restricted to compact myocardium contrasting with increased mitochondrial oxidative activity in the trabeculae. HIF1a regulation mirrors this pattern, with expression predominating in compact myocardium and scarce in trabeculae. By midgestation, the compact myocardium downregulates HIF1a and switches toward oxidative metabolism. Deletion of the E3 ubiquitin ligase Vhl results in HIF1a hyperactivation, disrupting metabolic compartmentalization and blocking the midgestational shift toward oxidative phosphorylation. Moreover, the altered glycolytic signature induced by HIF1 trabecular activation precludes regulation of genes essential for cardiac conduction system establishment. Our findings reveal VHL-HIF-mediated metabolic compartmentalization in the developing heart and the connection between metabolism and myocardial differentiation. These results highlight the importance of bioenergetics in ventricular myocardium specialization and its potential relevance to congenital heart disease.
Project description:T helper (Th) cell differentiation is driven by antigen and accessory signals that activate phosphoinositide 3-kinase (PI3K) to induce transcriptional and metabolic reprogramming including aerobic glycolysis (the Warburg effect). Here, we show that ATP generated through glycolysis fuels PI3K signaling to promote pathogenic Th17 cell responses. Mice with T cell-specific ablation of the glycolytic enzyme lactate dehydrogenase A (LDHA) were resistant to Th17 cell-mediated experimental autoimmune encephalomyelitis in association with defective T cell activation, migration, proliferation, and differentiation. LDHA deficiency crippled the cellular redox balance and inhibited ATP production causing attenuated phosphoinositide (3,4,5)-trisphosphate generation, and diminished activation of the Akt kinase and phosphorylation of its transcription factor target Foxo1. Th17 cell-specific expression of an Akt-insensitive Foxo1 mutant recapitulated the Th17 cell differentiation defects caused by LDHA deficiency. Thus, PI3K signaling and glycolytic bioenergetics constitute a positive feedback regulatory circuit essential for Th17 cell-mediated autoimmunity.