STIM1-mediated gene expression in non-pathogenic and pathogenic CD4+ Th17 cells

Immunity to fungal infections is mediated by cells of the innate and adaptive immune system. Activation of immune cells requires Ca2+ influx through the Ca2+ channel ORAI1, which is activated by stromal interaction molecule 1 (STIM1). Th17 cells are essential for immunity to C. albicans infection and require Ca2+ influx for expression of IL-17A and other Th17 cytokines. In mice, deletion of STIM1 and thus Ca2+ influx in all immune cells enhanced susceptibility to mucosal C. albicans infection, whereas T cell-specific deletion of STIM1 impaired immunity to systemic C. albicans infection. STIM1 deletion in CD4 T cells had different effects on gene expression programs in pathogenic (proinflammatory) and non-pathogenic Th17 cells. STIM1 deletion in non-pathogenic Th17 cells, which are required for antifungal immunity, compromised the expression of genes in several metabolic pathways including Foxo and HIF-1a signaling as well as the TCA cycle and oxidative phosphorylation (OXPHOS). Consequently, STIM1 deficient non-pathogenic Th17 cells had impaired glycolysis and mitochondrial respiration. By contrast, STIM1 deletion in pathogenic Th17 cells showed only attenuated mitochondrial function but normal glycolysis. Comparing transcriptome of WT and Stim1fl/fl Cd4Cre Th17 cells