Fig 1: Disrupting FABP5 in Tregs Triggers mtDNA Release and Consequent cGAS-STING-Dependent Type I IFN Signaling, Which Induces Heightened IL-10 ExpressionNaive CD4+ T cells were cultured for 3 days under Treg cell-differentiation conditions before overnight BMS309403 treatment.(A) Heatmap of the top 40 differentially regulated genes identified by RNA-seq.(B) Ingenuity pathway analysis of the top regulated pathways in Tregs after acute BMS309403 treatment.(C) Protein expression of pSTAT1Tyr701 in Tregs after FABP5 inhibition or Fabp5 shRNA. Results represent two independent experiments.(D) Representative confocal photomicrograph of mitochondrial staining and DNA in Tregs after overnight BMS309403 treatment. Scale bar, 2 µm.(E) Mean quantification (±SEM) of extra-nuclear and extra-mitochondrial nucleoid structures (n = 4). Results represent two independent experiments.(F) Quantification of cytosolic mtDNA content of Tregs after BMS309403 treatment (n = 3). Results represent two independent experiments.(G) Mean (±SEM) expression of type I IFN-related genes in Tregs after BMS309403 treatment with siRNA-mediated silencing of cGAS or STING measured by qPCR (n = 4). Results represent two independent experiments.(H) Mean (±SEM) expression of Il10 gene expression measured by qPCR (n = 4) in Tregs following overnight IFNa exposure (n = 4). Results represent two independent experiments.(I) Mean (±SEM) expression of Il10 gene expression measured by qPCR (n = 4) in IFNAR KO Tregs after overnight BMS309403 treatment (n = 4). Results represent two independent experiments.(J) Quantification of mean suppression (±SEM) from in vitro-differentiated IFNAR KO Tregs following overnight BMS309403 treatment (n = 4). Results represent three independent experiments. *p < 0.05, **p < 0.01, ***p < 0.005, ****p < 0.001. P values were calculated using a two-tailed, unpaired t test (E and H) or two-way ANOVA with Bonferroni correction (F, G, I, and J). Statistics shown in (G) are relative to the FABPi group.