Differential effects of glutamine inhibition strategies on anti-tumor CD8 T cell function. Differential effects of glutamine inhibition strategies on anti-tumor CD8 T cell function

Activated T cells undergo metabolic reprogramming to meet anabolic, differentiation, and functional demands. Glutamine supports many processes in activated T cells, and inhibition of glutamine metabolism alters T cell function in autoimmune disease and cancer. Multiple glutamine-targeting molecules are under investigation, yet the precise mechanisms of glutamine-dependent CD8 T cell differentiation remain unclear. We show that distinct strategies of glutamine inhibition by glutaminase-specific inhibition with small molecule CB-839, pan-glutamine inhibition with 6-diazo-5-oxo-L-norleucine (DON), or by glutamine deprivation (No Q) produce distinct metabolic differentiation trajectories in CD8 T cells. T cell activation with CB-839 treatment had a milder effect than DON or No Q treatment. A key difference was that CB-839-treated cells compensated with increased glycolytic metabolism, while DON and No Q-treated cells increased oxidative metabolism. However, all glutamine treatment strategies elevated CD8 T cell dependence on glucose metabolism, and No Q treatment caused adaptation toward reduced glutamine dependence. DON treatment reduced histone modifications and numbers of memory-like cells in adoptive transfer studies, but those T cells that persisted could expand normally upon secondary antigen encounter. In contrast, No Q-treated cells persisted well yet demonstrated decreased secondary expansion. Consistent with impaired function, CD8 T cells activated in the presence of DON had reduced ability to control tumor growth and reduced tumor infiltration in adoptive cell therapy. Overall, each approach to inhibit glutamine metabolism confers distinct effects on CD8 T cells and highlights that targeting the same pathway in different ways can elicit opposing metabolic and functional outcomes. Overall design: Uinsg RNAseq and CUT&RUN to profile how glutamine metabolism reprogram CD8+ T cell function.

活化T细胞会发生代谢重编程，以满足合成代谢、分化及功能需求。谷氨酰胺可支持活化T细胞中的诸多生理过程，而谷氨酰胺代谢抑制会在自身免疫病与癌症中改变T细胞的功能。目前已有多种靶向谷氨酰胺的分子处于研发阶段，但谷氨酰胺依赖的CD8阳性T细胞（CD8+ T cell）分化的确切机制仍不明确。
本研究证实，采用不同的谷氨酰胺抑制策略——使用小分子CB-839特异性抑制谷氨酰胺酶、使用6-重氮-5-氧代-L-正亮氨酸（6-diazo-5-oxo-L-norleucine, DON）进行泛谷氨酰胺抑制，或是通过剥夺谷氨酰胺（No Q）——可使CD8 T细胞产生截然不同的代谢分化轨迹。与DON处理或无谷氨酰胺（No Q）处理相比，CB-839处理组的T细胞活化效应更为温和。二者的关键差异在于：CB-839处理的细胞可通过增强糖酵解代谢进行代偿，而DON与No Q处理组的细胞则会上调氧化代谢水平。
不过，所有谷氨酰胺干预策略均会增强CD8 T细胞对葡萄糖代谢的依赖，而No Q处理可使细胞适应谷氨酰胺依赖度降低的状态。在过继转移实验中，DON处理会减少组蛋白修饰与记忆样细胞的数量，但存活下来的T细胞在再次遭遇抗原时可正常扩增。与之相反，No Q处理组的细胞存活能力良好，但二次扩增能力出现下降。与功能受损的表型一致，在过继细胞疗法中，经DON处理活化的CD8 T细胞，其肿瘤生长控制能力与肿瘤浸润能力均有所降低。
总体而言，每种抑制谷氨酰胺代谢的方法都会对CD8 T细胞产生差异化影响，这表明以不同方式靶向同一通路，可引发截然相反的代谢与功能结局。
研究设计：本研究采用RNA测序（RNAseq）与CUT&RUN技术，解析谷氨酰胺代谢如何重编程CD8+ T细胞的功能。