FIGURE 8.

IRAK3 is responsible for ligand desensitization under low methylation conditions. A, Western blot analysis of IRAK-3 levels in Huh7.5 cells treated with 10 μm AMI-1 for 16 h with or without 1 ng/ml FSL-1 for the indicated times. B, analysis of human blood derived macrophages. Basal mRNA level of IRAK3 is plotted against PRMT1/JMJD6 (left) or relative TRAF6 methylation (right). -Fold increase in IL6 mRNA after 1 h of LPS treatment is plotted against IRAK3 protein concentration (bottom). Each point represents an individual HBDM preparation, n = 26. C, NF-κB luciferase reporter assays in THP-1 cells that were either untreated (control) or treated with TLR6/2 (FSL-1), TLR4 (LPS) or TLR1/2 (Pam3) ligands as indicated. Cells were first transfected with negative control (NC) siRNA, PRMT1-specific siRNA, IRAK3-specific siRNA, or both IRAK3 and PRMT1 siRNA. Data are presented as the mean ± S.D. **, p < 0.01. n ≥ 3. ns, not significant.