CO generated by HO-1–dependent heme breakdown upregulates the PPP. (A) Schematic showing the release of CO from CORM3 upon reaction with water and the generation of inactivated CORM3 (iCORM3). (B) mRNA expression of Glut1, G6pd, and Pgd in BMDMs treated with vehicle, 35-70 µM CORM3, or 35-70 µM iCORM3 for 6 hours. (n = 4). Corresponding representative western blot analysis of G6PD and PGD protein in BMDMs treated with vehicle, 100 µM iCORM3 (iCO), or 50-100 µM CORM3 (CO) for 12 or 24 hours. (C) G6PD activity, measured as the rate of NAPDH synthesis, in BMDMs treated with vehicle, 100 µM CORM3, or 100 µM iCORM3 for 6 or 24 hours (n = 3-4). (D) Intracellular NADPH levels measured from BMDMs treated with vehicle, 50-100 µM CORM3, or 50-100 µM iCORM3 for 6 hours (n = 4). (E) mRNA expression of M1 macrophage markers in BMDMs treated with vehicle, iCORM3, or 50 µM CORM3 for 6 hours (n = 4). (F) mRNA expression of M2 macrophage markers in BMDMs treated with vehicle, iCORM3, or 50 µM CORM3 for 6 hours (n = 4). (G) mRNA expression of Mox macrophage markers in BMDMs treated with vehicle, iCORM3, or 50 µM CORM3 for 6 hours (n = 4). (H) Schematic representing feed-forward regulation of PPP by heme breakdown mediated by CO. 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. *P < .05; **P < .01; ***P < .001. See also supplemental Figure 4.