3 research outputs found
Global alteration of T-lymphocyte metabolism by PD-L1 checkpoint involves a block of de novo nucleoside phosphate synthesis
A platform for investigating immune checkpoint-mediated changes in metabolism
There is a growing interest in metabolomic profiling of immune cells, as there is accumulating evidence that metabolism influences immune cell function and fate decisions. The non-adherent nature of these cells presents certain challenges not factored into extraction protocols developed for adherent cells. Here, we present a method developed for metabolite extraction from human T-cells that emphasizes simplicity and economy. We apply this method to profile the metabolic changes effected by in-vitro programmed cell death 1 receptor (PDCD1/PD-1) immune checkpoint engagement by liquid chromatography and mass spectrometry. We demonstrate that we can efficiently confirm the known reduction in aerobic glycolysis and glutaminolysis that accompanies PD-1 signaling and extend this by showing a block in de novo nucleoside phosphate biosynthesis
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Global alteration of T-lymphocyte metabolism by PD-L1 checkpoint involves a block of de novo nucleoside phosphate synthesis.
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