Similar Datasets
Project description:Oxidative stress is caused by short-lived molecules and metabolic changes belong to the fastest cellular responses. Here we studied how the endothelial cell metabolome reacts to acute oxidative challenges (menadione or H2O2) to identify redox-sensitive metabolic enzymes. H2O2 selectively increased α-ketoglutaramate (αKGM), a largely uncharacterized metabolite produced by glutamine transamination and a yet unrecognized intermediate of endothelial glutamine catabolism. The enzyme nitrilase-like 2 ω-amidase (NIT2) converts αKGM to α-ketoglutarate (αKG). Reversible oxidation of specific cysteine in NIT2 by H2O2 inhibited its catalytic activity. Furthermore, a variant in the NIT2 gene that decreases its expression is associated with high plasma αKGM level in humans. Endothelial-specific knockout mice of NIT2 exhibited increased levels of αKGM and impaired angiogenesis. Knockout of NIT2 impaired endothelial cell proliferation and sprouting and induced senescence. In conclusion, we show that the glutamine transaminase-ω-amidase pathway is a metabolic switch in which NIT2 is the redox-sensitive enzyme. The pathway is modulated in humans and functionally important for endothelial glutamine metabolism.
2025-09-22 | PXD055885 | Pride
Project description:Oxidative stress is caused by short-lived molecules and metabolic changes are fast cellular responses. Here we studied how the endothelial cell metabolome reacts to oxidative challenges to identify redox-sensitive metabolic enzymes. H2O2 selectively increased α-ketoglutaramate (αKGM), a largely uncharacterized metabolite produced by glutamine transamination and an unrecognized intermediate of endothelial glutamine catabolism. The enzyme nitrilase-like 2 ω-amidase (NIT2) converts αKGM to α-ketoglutarate (αKG). Reversible oxidation of specific cysteine in NIT2 inhibited its catalytic activity. Furthermore, a variant in the NIT2 gene that decreases its expression is associated with increased plasma αKGM in humans. Endothelial-specific knockout mice of NIT2 exhibited increased levels of αKGM and impaired angiogenesis. Knockout of NIT2 impaired endothelial cell proliferation, sprouting and induced senescence. In conclusion, we show that the glutamine transaminase-ω-amidase pathway is a metabolic switch where NIT2 is the redox-sensitive enzyme. The pathway is modulated in humans and functionally important for endothelial glutamine metabolism.
2025-09-25 | GSE302821 | GEO
Project description:Oxidative stress is caused by short-lived molecules and metabolic changes are fast cellular responses. Here we studied how the endothelial cell metabolome reacts to oxidative challenges to identify redox-sensitive metabolic enzymes. H2O2 selectively increased α-ketoglutaramate (αKGM), a largely uncharacterized metabolite produced by glutamine transamination and an unrecognized intermediate of endothelial glutamine catabolism. The enzyme nitrilase-like 2 ω-amidase (NIT2) converts αKGM to α-ketoglutarate (αKG). Reversible oxidation of specific cysteine in NIT2 inhibited its catalytic activity. Furthermore, a variant in the NIT2 gene that decreases its expression is associated with increased plasma αKGM in humans. Endothelial-specific knockout mice of NIT2 exhibited increased levels of αKGM and impaired angiogenesis. Knockout of NIT2 impaired endothelial cell proliferation, sprouting and induced senescence. In conclusion, we show that the glutamine transaminase-ω-amidase pathway is a metabolic switch where NIT2 is the redox-sensitive enzyme. The pathway is modulated in humans and functionally important for endothelial glutamine metabolism.
2025-09-25 | GSE302820 | GEO
Project description:The transaminase-ω-amidase pathway is a redox switch in glutamine metabolism that generates α-ketoglutarate.
| PRJNA1292212 | ENA
Project description:The transaminase-ω-amidase pathway is a redox switch in glutamine metabolism that generates α-ketoglutarate [RNA-seq_NIT2_aKGM_4h_24h]
| PRJNA1292221 | ENA
Project description:The transaminase-ω-amidase pathway is a redox switch in glutamine metabolism that generates α-ketoglutarate [RNA-seq_NIT2-GLS1-KO]
| PRJNA1292220 | ENA
Project description:Many cancers utilize l-glutamine as a major energy source. Often cited in the literature as "l-glutamine addiction", this well-characterized pathway involves hydrolysis of l-glutamine by a glutaminase to l-glutamate, followed by oxidative deamination, or transamination, to α-ketoglutarate, which enters the tricarboxylic acid cycle. However, mammalian tissues/cancers possess a rarely mentioned, alternative pathway (the glutaminase II pathway): l-glutamine is transaminated to α-ketoglutaramate (KGM), followed by ω-amidase (ωA)-catalyzed hydrolysis of KGM to α-ketoglutarate. The name glutaminase II may be confused with the glutaminase 2 (GLS2) isozyme. Thus, we recently renamed the glutaminase II pathway the "glutamine transaminase-ω-amidase (GTωA)" pathway. Herein, we summarize the metabolic importance of the GTωA pathway, including its role in closing the methionine salvage pathway, and as a source of anaplerotic α-ketoglutarate. An advantage of the GTωA pathway is that there is no net change in redox status, permitting α-ketoglutarate production during hypoxia, diminishing cellular energy demands. We suggest that the ability to coordinate control of both pathways bestows a metabolic advantage to cancer cells. Finally, we discuss possible benefits of GTωA pathway inhibitors, not only as aids to studying the normal biological roles of the pathway but also as possible useful anticancer agents.
| S-EPMC10452834 | biostudies-literature
Project description:IntroductionCellular adaptation to physical training and energy metabolism play an important role during physical exercise. This study sought to investigate the effects of α-KG on cell growth and energy metabolism in C2C12 cell culture.MethodsC2C12 cells were cultured in media pretreated without (control) or with α-KG at different concentrations, and cells and media were harvested every 24 h for 8 days. From cell counts, specific cell growth rate (SGR) and doubling time were calculated. The content of glucose, glutamine, lactate, and ammonia in media was determined, and the specific consumption rate (SCR) or production rate (SPR) was calculated. Additionally, cell colony-forming efficiency (CFE) was determined.ResultsThe control cells showed a CFE at 50%, a typical cell growth curve in the first 5 days with a mean SGR at 0.86/day, and a mean cell count doubling time at 19.4 h. In the group with α-KG at 100 mM, the cells underwent rapid cell death, and thus no further analysis was made. The treatment with α-KG at lower concentrations (0.1 mM and 1.0 mM) led to a higher CFE at 68 and 55%, respectively, whereas those in groups with higher α-KG concentration decreased (10 and 6% for 20 mM and 30 mM α-KG, respectively). The mean SGR was 0.95/day, 0.94/day, 0.77/day, 0.71/day, and 0.65/day for groups treated with α-KG at 0.1, 1.0, 10.0, 20.0, and 30.0 mM, respectively, and the corresponding cell count doubling time was 17.6, 17.8, 20.9, 24.6, and 24.7 h, respectively. In comparison with that of the control group, the mean glucose SCR decreased in all the groups treated with α-KG, while the mean glutamine SCR remained unchanged; the mean lactate SPR increased in the groups treated with α-KG ≥ 20.0 mM. Finally, the mean SPR of ammonia was lower in all α-KG groups than that in the control.Discussion and conclusionThe treatment with α-KG at lower concentrations increased cell growth whereas at higher concentrations decreased cell growth, and α-KG reduced glucose consumption and ammonia production. Therefore, α-KG stimulates cell growth in a dose-dependent manner, which is likely through the improvement of glucose and glutamine metabolism in a C2C12 culture setting.
| S-EPMC10208397 | biostudies-literature
Project description:During erythroid differentiation, the erythron must remodel its protein constituents so that the mature red cell contains hemoglobin as the chief cytoplasmic protein component. For this, ∼109 molecules of heme must be synthesized, consuming 1010 molecules of succinyl-CoA. It has long been assumed that the source of succinyl-coenzyme A (CoA) for heme synthesis in all cell types is the tricarboxylic acid (TCA) cycle. Based upon the observation that 1 subunit of succinyl-CoA synthetase (SCS) physically interacts with the first enzyme of heme synthesis (5-aminolevulinate synthase 2, ALAS2) in erythroid cells, it has been posited that succinyl-CoA for ALA synthesis is provided by the adenosine triphosphate-dependent reverse SCS reaction. We have now demonstrated that this is not the manner by which developing erythroid cells provide succinyl-CoA for ALA synthesis. Instead, during late stages of erythropoiesis, cellular metabolism is remodeled so that glutamine is the precursor for ALA following deamination to α-ketoglutarate and conversion to succinyl-CoA by α-ketoglutarate dehydrogenase (KDH) without equilibration or passage through the TCA cycle. This may be facilitated by a direct interaction between ALAS2 and KDH. Succinate is not an effective precursor for heme, indicating that the SCS reverse reaction does not play a role in providing succinyl-CoA for heme synthesis. Inhibition of succinate dehydrogenase by itaconate, which has been shown in macrophages to dramatically increase the concentration of intracellular succinate, does not stimulate heme synthesis as might be anticipated, but actually inhibits hemoglobinization during late erythropoiesis.
| S-EPMC6128084 | biostudies-literature
Project description:The efficacy of apatinib has been confirmed in the treatment of solid tumors, including non-small-cell lung cancer (NSCLC). However, the direct functional mechanisms of tumor lethality mediated by apatinib and the precise mechanisms of drug resistance are largely unknown. In this study, we demonstrated that apatinib could reprogram glutamine metabolism in human NSCLC via a mechanism involved in amino acid metabolic imbalances. Apatinib repressed the expression of GLS1, the initial and rate-limiting enzyme of glutamine catabolism. However, the broken metabolic balance led to the activation of the amino acid response (AAR) pathway, known as the GCN2/eIF2α/ATF4 pathway. Moreover, activation of ATF4 was responsible for the induction of SLC1A5 and ASNS, which promoted the consumption and metabolization of glutamine. Interestingly, the combination of apatinib and ATF4 silencing abolished glutamine metabolism in NSCLC cells. Moreover, knockdown of ATF4 enhanced the antitumor effect of apatinib both in vitro and in vivo. In summary, this study showed that apatinib could reprogram glutamine metabolism through the activation of the AAR pathway in human NSCLC cells and indicated that targeting ATF4 is a potential therapeutic strategy for relieving apatinib resistance.
| S-EPMC9304404 | biostudies-literature