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  • The malate shuttle detoxifies ammonia in exhausted T cells by producing 2-ketoglutarate.

The malate shuttle detoxifies ammonia in exhausted T cells by producing 2-ketoglutarate.

Nature immunology (2023-10-10)
Nina Weisshaar, Sicong Ma, Yanan Ming, Alaa Madi, Alessa Mieg, Marvin Hering, Ferdinand Zettl, Kerstin Mohr, Nora Ten Bosch, Diana Stichling, Michael Buettner, Gernot Poschet, Glynis Klinke, Michael Schulz, Nina Kunze-Rohrbach, Carolin Kerber, Isabel Madeleine Klein, Jingxia Wu, Xi Wang, Guoliang Cui
ABSTRACT

The malate shuttle is traditionally understood to maintain NAD+/NADH balance between the cytosol and mitochondria. Whether the malate shuttle has additional functions is unclear. Here we show that chronic viral infections induce CD8+ T cell expression of GOT1, a central enzyme in the malate shuttle. Got1 deficiency decreased the NAD+/NADH ratio and limited antiviral CD8+ T cell responses to chronic infection; however, increasing the NAD+/NADH ratio did not restore T cell responses. Got1 deficiency reduced the production of the ammonia scavenger 2-ketoglutarate (2-KG) from glutaminolysis and led to a toxic accumulation of ammonia in CD8+ T cells. Supplementation with 2-KG assimilated and detoxified ammonia in Got1-deficient T cells and restored antiviral responses. These data indicate that the major function of the malate shuttle in CD8+ T cells is not to maintain the NAD+/NADH balance but rather to detoxify ammonia and enable sustainable ammonia-neutral glutamine catabolism in CD8+ T cells during chronic infection.

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GSK-J4, ≥98% (HPLC)