A, B, Silencing TRAF3IP2 attenuates IL-18-induced collagen mRNA expression. CF transfected with modified and unmodified TRAF3IP2 siRNA were made quiescent, incubated with IL-18 (10 ng/ml for 2 h), and analyzed for collagens type 1a1 (A) and collagen type 3a1 (B) mRNA expression by RT-qPCR. Collagen I and III protein levels were analyzed by immunoblotting using cleared whole cell homogenates (respective lower panel; n=3). A, B, *P< 0.001 vs. untreated, †P< at least 0.05 vs. IL-18 (n=6). C, IL-18-stimulated collagen secretion is TRAF3IP2 dependent. CF treated as in A and B, but for 24 h with IL-18, were analyzed for recently synthesized collagens by Sircol collagen assay, normalized to cell numbers, and expressed as fold change from untreated. *P< 0.001 vs. untreated, †P< 0.01 vs. IL-18 (n=8).