Immunometabolite L-2-HG promotes epigenetic modification of exhausted T cells and improves anti-tumor immunity.

This study aimed to explore the potential correlation between the metabolic intermediate L-2-hydroxyglutarate (L-2-HG) and T cell exhaustion, as well as the underlying mechanisms involved. In this study, we investigated the presence of exhausted T cells (Tex) in patients under certain conditions: HIV infection, chronic leukemia, and hepatocellular carcinoma. To gain insights into the epigenetic signatures and transcriptome alterations in Tex, we employed a combination of RNA-seq and ATAC-seq analyses. To evaluate the impact of L-2-HG on mitochondrial function, differentiation, and anti-tumor capacity of Tex, we utilized in vitro cell culture experiments and animal tumor models. We observed mitochondrial depolarization and metabolic dysfunction in Tex, accompanied by a significant reduction in the metabolic intermediate L-2-HG level. Moreover, altered epigenetic characteristics was observed in Tex, including a substantial increase in H3K27me3 abundance. Culturing Tex with L-2-HG demonstrated improved mitochondrial metabolism, reduced H3K27me3 abundance, and enhanced memory T cell differentiation. In the mouse melanoma tumor model, L-2-HG-treated CD8+T cells for adoptive therapy led to significantly reduced tumor volume and significantly enhanced effector function of T cells. The study revealed L-2-HG acted as an immune metabolite through epigenetic modifications of Tex.