Glycolysis Promotes Phosphoinositide 3-Kinase Signaling In Support of T Helper 17 Cell-Mediated Autoimmunity

T helper (Th) cell differentiation is driven by antigen and accessory signals that activate phosphoinositide 3-kinase (PI3K) to induce transcriptional and metabolic reprogramming including aerobic glycolysis (the Warburg effect). Here, we show that ATP generated through glycolysis fuels PI3K signaling to promote pathogenic Th17 cell responses. Mice with T cell-specific ablation of the glycolytic enzyme lactate dehydrogenase A (LDHA) were resistant to Th17 cell-mediated experimental autoimmune encephalomyelitis in association with defective T cell activation, migration, proliferation, and differentiation. LDHA deficiency crippled the cellular redox balance and inhibited ATP production causing attenuated phosphoinositide (3,4,5)-trisphosphate generation, and diminished activation of the Akt kinase and phosphorylation of its transcription factor target Foxo1. Th17 cell-specific expression of an Akt-insensitive Foxo1 mutant recapitulated the Th17 cell differentiation defects caused by LDHA deficiency. Thus, PI3K signaling and glycolytic bioenergetics constitute a positive feedback regulatory circuit essential for Th17 cell-mediated autoimmunity. WT and LDHA-KO Th17 cells were subjected to RNA-Seq analysis. (2 samples in each group)