The transaminase-ω-amidase pathway senses oxidative stress to control glutamine metabolism and α-ketoglutarate levels in endothelial cells

Oxidative stress is a major driver of cardiovascular disease; however, the fast changes in cellular metabolism caused by short-lived reactive oxygen species (ROS) remain ill-defined. Here, we characterized changes in the endothelial cell metabolome in response to acute oxidative challenges and identified novel redox-sensitive metabolic enzymes. H<sub>2</sub>O<sub>2</sub> selectively increased the amount of α-ketoglutaramate (αKGM), a largely uncharacterized metabolite produced by glutamine transamination and an unrecognized intermediate of endothelial glutamine catabolism. In addition, H<sub>2</sub>O<sub>2</sub> impaired the catalytic activity of nitrilase-like 2 ω-amidase (NIT2), the enzyme that converts αKGM to α-ketoglutarate (αKG), by the reversible oxidation of specific cysteine residues. Moreover, a NIT2 gene variant exhibited decreased expression in humans and was associated with increased plasma αKGM concentration. Endothelial-specific knockout of NIT2 in mice increased cellular αKGM levels and impaired angiogenesis. Further, NIT2 depletion impaired endothelial cell proliferation, sprouting, and induced senescence. In conclusion, we uncover NIT2 as a redox-sensitive enzyme of the glutamine transaminase-ω-amidase pathway that acts as a metabolic switch modulating endothelial glutamine metabolism in mice and humans.

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Journal
The EMBO Journal
Published
2025-12-17
DOI
https://doi.org/10.1038/s44318-025-00642-7
Primary Topic
Cancer, Hypoxia, and Metabolism
Type
article
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article

The transaminase-ω-amidase pathway senses oxidative stress to control glutamine metabolism and α-ketoglutarate levels in endothelial cells

Ewgenij Proschak, Ilka Wittig, Stephan Klatt, Tamim Sarakpi et al.
The EMBO Journal
Cancer, Hypoxia, and Metabolism
article

The transaminase-ω-amidase pathway senses oxidative stress to control glutamine metabolism and α-ketoglutarate levels in endothelial cells

Ewgenij Proschak, Ilka Wittig, Stephan Klatt, Tamim Sarakpi, Ina Koch, Melina Lopez, Ralf Gilsbach, Stefanie Dimmeler, Thimoteus Speer, Tom Teichmann, Steffen Brunst, Jonel Trebicka, Sofia‐Iris Bibli, Pedro Felipe Malacarne, J. Brent Richards, Timothy Warwick, Luciana Hannibal, Flávia Rezende, Mónica Rosas‐Lemus, Travis T. Denton, Julian U. G. Wagner, Amparo Acker‐Palmer, Frank Erhard Uschner, Nina Baumgarten, Sabine Klein, Matthias S. Leisegang, Stefan Günther, Marcus Keßler, Marcel H. Schulz, Ralf P. Brandes, Maria-Kyriaki Drekolia, Ingrid Fleming, Yiheng Chen, Marta Segarra, Niklas Herrle, Sarah Wionski, Maedeh Gheisari, Souradeep Chatterjee, Alfredo Cabrera-Orefice, Carine Kader
article en

Abstract

Oxidative stress is a major driver of cardiovascular disease; however, the fast changes in cellular metabolism caused by short-lived reactive oxygen species (ROS) remain ill-defined. Here, we characterized changes in the endothelial cell metabolome in response to acute oxidative challenges and identified novel redox-sensitive metabolic enzymes. H<sub>2</sub>O<sub>2</sub> selectively increased the amount of α-ketoglutaramate (αKGM), a largely uncharacterized metabolite produced by glutamine transamination and an unrecognized intermediate of endothelial glutamine catabolism. In addition, H<sub>2</sub>O<sub>2</sub> impaired the catalytic activity of nitrilase-like 2 ω-amidase (NIT2), the enzyme that converts αKGM to α-ketoglutarate (αKG), by the reversible oxidation of specific cysteine residues. Moreover, a NIT2 gene variant exhibited decreased expression in humans and was associated with increased plasma αKGM concentration. Endothelial-specific knockout of NIT2 in mice increased cellular αKGM levels and impaired angiogenesis. Further, NIT2 depletion impaired endothelial cell proliferation, sprouting, and induced senescence. In conclusion, we uncover NIT2 as a redox-sensitive enzyme of the glutamine transaminase-ω-amidase pathway that acts as a metabolic switch modulating endothelial glutamine metabolism in mice and humans.

The EMBO JournalVol. 45(3)
Goethe University Frankfurt (DE), University of Freiburg (DE), University of New Mexico (US), Washington State University Spokane (US), University of Mannheim (DE), King's College London (GB), Heidelberg University (DE), University Medical Center Freiburg (DE), Frankfurt Institute for Advanced Studies (DE), McGill University Health Centre (CA), Jewish General Hospital (CA), University Hospital Heidelberg (DE), Max Planck Institute for Heart and Lung Research (DE), University Hospital Münster (DE), German Centre for Cardiovascular Research (DE), Else Kröner-Fresenius-Stiftung (DE), McGill University (CA)
Openalex Percentile: Top 51%
Cancer, Hypoxia, and Metabolism
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