GSE196315
D- 2-hydroxyglutarate is an immunometabolite that accumulates in macrophages after TLR activation and inhibits inflammatory responses
Macrophages undergo extensive metabolic rewiring upon activation and this serves many roles beyond the production of energy and anabolic building blocks. So-called immunometabolites that accumulate upon immune activation can serve as co-factors for enzymes and can mediate posttranslational modifications of histones, transcription factors, enzymes and other key proteins that modulate macrophage function. As such, the Krebs-cycle-associated metabolites succinate and itaconate emerged as key regulators of macrophages. 2-hydroxyglutarate (2HG) is structurally similar to Krebs-cycle metabolite alpha-ketoglutarate and exists as two enantiomers. D-2HG is well studied as an oncometabolite in cancer cells and more recently, L-2HG received some attention in the immunometabolism field. Here we describe that 2HG levels peak during later stages of LPS-induced inflammatory responses in mouse and human macrophages. Surprisingly, D-2HG was the most abundant enantiomer in macrophages and its LPS-induced accumulation may be explained by the inverse kinetics of D-2HG-degrading D-2HG dehydrogenase (D2HGDH) and the time-dependent induction of Hydroxyacid-Oxoacid Transhydrogenase (HOT), which makes D-2HG as a byproduct. D-2HG kinetics fit transcriptomics and functional data, together indicating that D-2HG suppresses inflammatory responses in macrophages in vitro. D-2HG also regulates local and systemic inflammatory responses in vivo. Finally, we show that D-2HG likely exerts in anti-inflammatory effects on NFkB target genes independently of aKG-dependent dioxygenases. Together, this study unexpectedly classifies D-2HG as an immunometabolite that can inhibit inflammatory macrophage responses. Overall design: RNA-seq of bone marrow-derived macrophages from WT C57Bl/6 mice to assess effect of D2HG octyl ester on LPS responses.