Glycolysis Fuels Phosphoinositide 3-Kinase Signaling to Bolster T Cell Immunity

Infection triggers clonal expansion and effector differentiation of microbial antigen-specific T cells in association with metabolic reprograming. Here, we show that the glycolytic enzyme lactate dehydrogenase A (LDHA) is induced in CD8+ T effector cells via phosphoinositide 3-kinase (PI3K)-dependent mechanisms. In turn, ablation of LDHA inhibits PI3K-dependent phosphorylation of Akt and its transcription factor target Foxo1, causing defective antimicrobial immunity. LDHA deficiency cripples cellular redox control and diminishes glycolytic adenosine triphosphate (ATP) production in effector T cells, resulting in attenuated PI3K signaling. Thus, nutrient metabolism and growth factor signaling are highly integrated processes with glycolytic ATP serving as a rheostat to gauge PI3K/Akt/Foxo1 signaling in T cell immunity control. Such a bioenergetics mechanism of signaling regulation implies a root cause for the century-old phenomenon of Warburg effect, and could guide development of novel therapeutics for infectious diseases and cancer.