Fig. 3.

LDHi increases the contribution of glucose to the TCA cycle in IL-2–treated cells and alters mitochondrial metabolism. (A) Corrected ¹³C-labeled fraction of TCA cycle intermediates from ¹³C-glucose in IL-2– and IL-21–treated cells in the absence or presence of LDHi, assessed by LC-MS. Measurements are displayed as total distribution of labeled fractions ranging from the unlabeled mass of the metabolite, M, to the mass plus the addition of six ¹³C-labeled atoms (M+6). (B) OCR of cells treated with IL-2, IL-2+LDHi, IL-21, or IL-21+LDHi following injection with oligomycin, FCCP, and antimycin A/rotenone. (C and D) Quantitative measurements of ECAR (C) and SRC (D) for cells treated with IL-21, IL-21+LDHi, IL-2, or IL-2+LDHi, as indicated. (E) Ldha-deletion in T cells. Western blot demonstrating the absence of LDHA following tamoxifen-mediated deletion of Ldha (Materials and Methods). (F and G) Graphs showing ECAR (F) and SRC (G) measurements for WT and Ldha KO cells. **P < 0.01; ****P < 0.0001; ns, not significant.