Fig. 5.
The anti-inflammatory effect of TQ is dependent on AhR. (A) The anti-inflammatory effect of TQ, as measured by the mRNA levels of IL-6 in U937 cells upon activation with LPS, was prevented by the competitive inhibitor of AhR, GNF-531 (20 μM). Other AhR inhibitors SGA-360 (20 μM) and CH-223191 (10 μM) failed to inhibit the anti-inflammatory effect of TQ. (B) CRISPR/Cas9-mediated targeting of the AHR gene produced a complete knockout of AhR in U937 cells. The GAPDH levels are shown as the loading control. (C–E) In the absence of AhR, TQ failed to prevent the LPS-induced upregulation in the mRNA levels of IL-1β (C), IL-6 (D), and TNF-α (E) by U937 cells. Scr- non-target scrambled control. (F) TQ did not prevent the LPS-induced upregulation of IL-1β, IL-6, IL-23, and TNF-α mRNA levels in the Ahr−/− mouse splenocytes (n = 3/group). Data represented as mean ± SEM, n ≥ 3 from 3 independent experiments. One-way analysis of variance with Tukey’s post test. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. ns = not significant.