Metabolic obstacles of the tumor microenvironment remain a challenge to T-cell-mediated cancer immunotherapies. To better understand the interplay of immune checkpoint signaling and immune metabolism, this study developed and used an optimized metabolite extraction protocol for non-adherent primary human T-cells, to broadly profile in vitro metabolic changes effected by PD-1 signaling by mass spectrometry-based metabolomics and isotopomer analysis. Inhibitory signaling reduced aerobic glycolysis and glutaminolysis. A general scarcity across the panel of metabolites measured supported widespread metabolic regulation by PD-1. Glucose carbon fate analysis supported tricarboxylic acid cycle reliance on pyruvate carboxylation, catabolic-state fluxes into acetyl-CoA and succinyl-CoA, and a block in de novo nucleoside phosphate synthesis that was accompanied by reduced mTORC1 signaling. Nonetheless, exogenous administration of nucleosides was not sufficient to ameliorate proliferation of T-cells in the context of multiple metabolic insufficiencies due to PD-L1 treatment. Carbon fate analysis did not support the use of primarily glucose-derived carbons to fuel fatty acid beta oxidation, in contrast to reports on T-memory cells. These findings add to our understanding of metabolic dysregulation by PD-1 signaling and inform the effort to rationally develop metabolic interventions coupled with immune-checkpoint blockade for increased treatment efficacy.

中文翻译：

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PD-L1检查点对T淋巴细胞代谢的整体改变涉及从头合成核苷磷酸合成的障碍。

肿瘤微环境的代谢障碍仍然是对T细胞介导的癌症免疫疗法的挑战。为了更好地了解免疫检查点信号与免疫代谢之间的相互作用，本研究针对非粘附原代人T细胞开发并使用了优化的代谢物提取方案，以广泛地描述质谱分析PD-1信号影响的体外代谢变化，基础的代谢组学和同位素异构体分析。抑制性信号传导减少有氧糖酵解和谷氨酰胺分解。所测量的代谢物总体上的稀缺性支持了PD-1广泛的代谢调节。葡萄糖碳命运分析支持三羧酸循环依赖于丙酮酸羧化，分解代谢成乙酰辅酶A和琥珀酰辅酶A的状态通量，以及从头合成磷酸核苷的过程受到阻碍，并伴有mTORC1信号转导减少。然而，在由于PD-L1治疗引起的多种代谢不足的情况下，外源给予核苷不足以改善T细胞的增殖。与关于T记忆细胞的报道相反，碳命运分析不支持主要使用葡萄糖衍生的碳来促进脂肪酸β氧化。这些发现增加了我们对PD-1信号传导代谢失调的理解，并为合理开发代谢干预措施和免疫检查点封锁以提高治疗效果提供了依据。在PD-L1治疗引起的多种代谢不足的情况下，外源性给予核苷不足以改善T细胞的增殖。与关于T记忆细胞的报道相反，碳命运分析不支持主要使用葡萄糖衍生的碳来促进脂肪酸β氧化。这些发现增加了我们对PD-1信号传导代谢失调的理解，并为合理开发代谢干预措施和免疫检查点封锁以提高治疗效果提供了依据。在PD-L1治疗引起的多种代谢不足的情况下，外源性给予核苷不足以改善T细胞的增殖。与关于T记忆细胞的报道相反，碳命运分析不支持主要使用葡萄糖衍生的碳来促进脂肪酸β氧化。这些发现增加了我们对PD-1信号传导代谢失调的理解，并为合理开发代谢干预措施和免疫检查点封锁以提高治疗效果提供了依据。