Involvement of OmA20 on MAPK and NF-κB activation in RTH-149 cells stimulated with LPS. (A) After stimulating RTH-149 cells with LPS (10 μg/mL) for the indicated time periods, phosphorylated, and total levels of TAK1, p38 MAPK, and JNK were determined by western blot analysis. (B) RTH-149 cells, co-transfected with pNF-κB-Luc and pRL-TK for 48 h, were stimulated with LPS (10 μg/mL) for the indicated time periods. Then, NF-κB activity was determined using a dual-luciferase reporter assay system. (C) RTH-149 cells, transfected with His-OmA20, EGFP-His, OmA20 siRNA, or non-specific siRNA for 48 h, were stimulated with LPS (10 μg/mL) for 12 h. Then, phosphorylated and total levels of TAK1, p38 MAPK, and JNK were determined by western blot analysis. (D) RTH-149 cells, co-transfected with a His-OmA20 or EGFP-His along with pNF-κB-Luc and pRL-TK for 48 h, were stimulated with LPS (10 μg/mL) for 12 h. Then, NF-κB activity was determined using a dual-luciferase reporter assay system. * p < 0.05, ** p < 0.01, *** p < 0.001 unstimulated control vs. LPS-stimulated cells; ●●● p < 0.001 EGFP-His vs. His-OmA20.