CO mimics the metabolic phenotype of heme-loaded macrophages. (A) MST of BMDMs treated with vehicle, 100 µM iCORM3, or 100 µM CORM3 for 6 hours (n ≥3). The OCR was measured initially (basal; blue) and after injection of 1 µM oligomycin, 2 µM BAM15 (maximal; green), 10 µM antimycin A, and 1 µM rotenone (gray; non-mitochondrial). Basal and maximal OCR were calculated by subtracting the mean OCR of the first 3 (basal) or post-BAM15 (maximal) measurements from the mean OCR of the post-AA/Rot measurements. Reserve capacity is the difference in maximal and basal respiratory capacity. (B) GST of BMDMs treated with vehicle, 100 µM iCORM3, or 100 µM CORM3 for 6 hours (n ≥3). The ECAR was measured after injection of 20 mM glucose, 1µM oligomycin, and 80 mM 2-deoxyglucose (2-DG) to produce the basal (blue), stressed (green), and background (gray) ECAR, respectively. Basal and stressed ECAR were calculated by subtracting the mean ECAR of the post-glucose (basal) or post-oligomycin (stressed) measurements from the mean ECAR of the post-2-DG measurements. (C) Bioenergetics plot relates the respiratory capacity of the cells (based on maximal OCR; y-axis) to the glycolytic capacity (based on stressed ECAR; x-axis) in BMDMs treated with CORM3 or iCORM3 for 6 hours (n ≥3). (D) as measured by luminescent signal of the Cell-Titer Glo ATP Assay and presented as percent of initial vehicle control (n = 5). Data are represented as mean ± SEM. Statistical significance between 2 groups was determined by Welch’s unpaired t test. Significance between more than 2 groups was determined by one-way ANOVA with post hoc Tukey’s or Dunnett’s multiple comparisons tests, as appropriate, to determine differences between specific groups. ns, not significant. *P < .05; **P < .01; ***P < .001. See also supplemental Figure 5.