Figure 5. Dose-Dependent Inhibition of Imd Signaling by ThT in Cells and in Flies.

(A and B) S2* cells were treated with ThT before triggering the activation of the Imd pathway with DAP-type PGN (A), or the Toll pathway with recombinant cleaved Spätzle, Spz-C106 (B). Transcript levels of the target genes for the Imd and Toll pathways, Diptericin and Drosomycin, respectively, were measured by qRT-PCR and normalized to Rp49 expression. Graph shows individual data points from 3 or 4 independent experiments, the line indicating the mean.

(C and D) ThT suppresses Diptericin induction in flies. w¹¹¹⁸ male and female flies were co-injected with vehicle (5% DMSO in sterile PBS), and 1 mM ThT ± 0.5 mg/mL PGN (C) or 40 μM TCT (D), and harvested 1 hr after injection. Diptericin transcript levels were measured by qRT-PCR and normalized to Rp49 values. Data shown are individual data points of six (C) and five (D) biological replicates, the bar indicating the mean.

(E) Inhibition of the Imd pathway activation by ThT is dose dependent. Male flies were injected with vehicle (5% DMSO in sterile PBS), 0.2 mM, 0.5 mM, or 1 mM ThT ± 0.5 mg/mL PGN and harvested 1 hr after injection. Diptericin transcript levels were measured by qPCR and normalized to Rp49 values. Data shown are individual data points of five biological replicates, the bar indicating the mean.

NS = not significant, **p < 0.01, ***p < 0.001, ****p < 0.0001. See further analysis of ThT inhibitor effects on Imd signaling in Figures S2 and S3.