Figure 5. MYC-mediated lactate formation suppresses a subset of LPS-induced proinflammatory cytokines.

(A) Diagram of metabolic inhibitors and their target processes.

(B) WT BMDMs were treated with 2-DG (5 mM) for 0.5 h and then stimulated with LPS (10 ng/ml) for 24 h. The level of inflammatory cytokines in supernatants was analyzed (n ≥ 3).

(C) WT BMDMs were treated with UK-5099 (100 μM) for 3 h and then stimulated with LPS (10 ng/ml) for 6 h. The mRNA expression of inflammatory cytokines was analyzed by qRT-PCR (n = 6).

(D) WT BMDMs from C57BL/6 were treated with FX11 (20 μM) for 3 h and then stimulated with LPS (10 ng/ml) for 6 h. The mRNA expression of inflammatory cytokines was analyzed by qRT-PCR (n = 6).

(E) WT and MYC cKO BMDMs were treated with lactic acid (LA; 100 mM) for 0.5 h and then stimulated with LPS (10 ng/ml) for 24 h. The level of IL-6, IL-12 p70, and IL-23 in supernatants was analyzed (n = 3).

(F and G) The enzymatic activity of lactate dehydrogenase (LDH) in WT and MYC cKO BMDMs (F; n = 3) or mock-infected or MYC-transduced BMDMs (G; n = 4) after LPS (100 ng/ml) stimulation for 6 h.

(H and I) The expression of lactate dehydrogenase A (LDHA) in WT and MYC cKO BMDMs (H) or mock-infected or MYC-transduced BMDMs (I) was determined by immunoblot using total lysates after LPS (100 ng/ml) stimulation for 6 h and quantified by densitometry (n = 5). α-Tubulin served as a loading control. Data are representative of 5 experiments.

(J) A schematic diagram illustrating the experimental design in (K).

(K) Twelve-week-old female C57BL/6 mice were treated with vehicle or FX11 (2.5 μg/g) on day −1 and day 0 and infected with Listeria monocytogenes on day 0. Bacterial titers in the spleen were determined on day 3 after infection (n ≥ 10).

All data are shown as mean ± SEM. *p < 0.05 by one-way ANOVA (B–D and H) or two-way ANOVA (E–G) with a post hoc Tukey test or two-tailed, paired t test (I and K).