Fig. 3.

dsRNA-responsive cell lines require TLR3 and respond to additional inflammatory stimuli. (A) Western blot depicting the expression of TLR3, RIG-I, and MDA5 in four poly (I:C)–responsive and four unresponsive cell lines. Both the full length (FL) and an active C-terminal fragment (CT) of TLR3 are shown. (B and C) Western blots showing the change in pSTAT1, total STAT1, and TLR3 after treatment with 30 μg/mL of poly (I:C) for 24 h with or without CRISPR-Cas9–mediated knockout of TLR3 in the SH-EP (B) and GI-ME-N (C) cell lines. (D) Western blot showing change in pSTAT1, total STAT1, and TLR3 after treatment with poly (I:C) for 24 h with or without expression of exogenous TLR3. (E) Difference in transcript expression of genes in the TLR3 signaling pathway between responsive and unresponsive cell lines as measured by QuantSeq. (F) Relative luminescence in the indicated cell lines transfected with an NF-κB reporter after treatment with a vehicle control or the indicated TLR agonists for 6 h. Table showing the agonists used in the adjacent experiments. Western blots are representative of results from at least three separate experiments. Either a two-tailed t test (E) or an ANOVA (F) was performed: *P < 0.05 and **P < 0.01. Error bars represent SEM between biological replicates.