Figure 3.

Effects of palmitate (PA) and IGFBP-3 (IBP3) on IL-8 expression in Huh-7 hepatocytes. A, B) Palmitate produced a dose-dependent increase in IL-8 mRNA (B), which peaked at 9 h after exposure (A). C) This was associated with activation of JNK and NF-κB. Conditioned medium from PMA-activated THP-1 macrophages that were preconditioned with palmitate that was deficient in IGFBP-3 led to a 20-fold increase in IL-8 mRNA, whereas conditioned medium from PMA-activated THP-1 macrophages that were without prior preconditioning had no significant effects. D) Addition of palmitate to PMA-activated THP-1 macrophage conditioned medium led to an increase in IL-8 mRNA (bar 4 vs. 1). Similarly, addition of palmitate to IGFBP-3–deficient medium from PMA-activated THP-1 macrophages that were preconditioned with palmitate led to a further increase in IL-8 mRNA. E) Exposure to recombinant IGFBP-3 led to a marked suppression of palmitate-induced IL-8 mRNA expression. F) Effects of silencing or overexpression of IGFBP-3 in THP-1 cells on Huh-7 cells IL-8 mRNA expression was also evaluated. Control vectors had no effect on palmitate-induced IL-8 expression, whereas silencing and overexpression had an inverse relationship to hepatocyte IL-8 mRNA expression. Ctrl, control; UT, untreated cells. Means ± sd from 3 independent experiments are shown for all graphical data.