Extracellular-acidosis restricts one-carbon metabolism and preserves T cell stemness: CUT&Tag. Extracellular-acidosis restricts one-carbon metabolism and preserves T cell stemness: CUT&Tag

The accumulation of acidic metabolic waste products within the tumor microenvironment profoundly inhibits effector functions of tumor-infiltrating lymphocytes (TILs). However, it is unclear whether extracellular-acidosis impacts T cell metabolic fitness and differentiation status. Here, we surprisingly found that prolonged acid exposure reprogrammed T cell intracellular metabolism and mitochondrial fitness, and preserved T cell stemness. Elevated extracellular-acidosis impaired methionine uptake and metabolism via downregulating SLC7A5, therefore altering H3K27me3 deposition at the promoters of crucial T cell stemness genes. These changes promoted the maintenance of a “stem-like memory” state and improved long-term in vivo persistence and anti-tumor efficacy. Our findings not only reveal the unexpected roles of extracellular-acidosis in the maintenance of stem-like properties of T cells, but also advance our understanding of the direct involvement of methionine metabolism in T cell stemness. Overall design: Cleavage Under Targets and Tagmentation (CUT&Tag) for the histone modifications H3K27me3and H3K4me3 in human T cells under control, lactic acid and lactic acid with 800μM methionine conditions.

肿瘤微环境内酸性代谢废物的积累，会显著抑制肿瘤浸润淋巴细胞（TILs）的效应功能。然而目前尚不清楚细胞外酸中毒是否会影响T细胞的代谢适应性与分化状态。本研究中，我们意外发现，长期酸性暴露可重编程T细胞的细胞内代谢与线粒体适应性，并维持T细胞干性。升高的细胞外酸中毒可通过下调溶质载体家族7成员5（SLC7A5）的表达，损伤甲硫氨酸的摄取与代谢，进而改变关键T细胞干性基因启动子区域的H3K27me3沉积水平。这些变化可促进"干细胞样记忆"状态的维持，并提升T细胞在体内的长期持久性与抗肿瘤功效。本研究的发现不仅揭示了细胞外酸中毒在维持T细胞干细胞样特性中的意外作用，还加深了我们对甲硫氨酸代谢直接参与T细胞干性调控的理解。整体实验设计：针对对照组、乳酸处理组以及添加800μM甲硫氨酸的乳酸处理组中的人T细胞，进行组蛋白修饰H3K27me3与H3K4me3的靶向切割与标签化（CUT&Tag）检测。