IFNγ induces NAMPT expression and IFNγ-induced increases in OCR are NAMPT-dependent. (A) Metabolic pathway analysis determined by the ERGO™ analysis platform based on differential gene expression from RNA-Seq data shown in panel B. (B) RNA sequencing of human monocyte–derived macrophages stimulated with IFNγ for 24 hours. (C) Diagram representing both NAM/NAMPT and nicotinamide ribose (NR)/NRK2-dependent NAD⁺ salvage pathways. (D) OCR measured by Seahorse in primary human monocytes treated with media alone or IFNγ with or without NAMPT inhibitor, FK866 (5 nM), for 24 hours prior to the start of the assay (n = 5 technical replicates). Data in panel D are from a representative tracing from 3 independent experiments. (E) Basal and PMA-stimulated OCR values from 3 independent experiments are summarized following normalization to the basal OCR values from samples without IFNγ, FK866, or PMA treatment. Data in panel E were analyzed by 2-way ANOVA with Sidak’s multiple comparisons test. Error bars are mean ± standard error of the mean. **P < .01, ***P < .001, ****P < .0001.