Fig. 4.

Sodium salt of lauric acid (C12:0) or sodium salt of palmitic acid (C16:0) without being complexed with BSA activated the downstream signaling pathways of pattern recognition receptors (PRRs). A: RAW 264.7 cells were serum-starved in 0.25% FBS/DMEM for 6 h and then treated with 300 µM C12:0 in the same low-serum medium for indicated times. B, C: RAW 264.7 cells were serum-starved as in A. The cells were then pretreated with indicated concentrations of DHA for 1 h followed by coincubation with 300 µM C12:0 for 15 min (B) or 100 µM C12:0 for 18 h (C). (D) THP-1 cells were serum-starved in 0.25% FBS/RPMI1640 medium for 12 h and then treated with 150 µM C16:0 in the same low-serum medium for indicated times. Protein lysates from A to D were probed for phosphorylated JNK (JNK-p), JNK, phosphorylated ERK (ERK-p), ERK, phosphorylated I κ B α (I κ B α -p), I κ B α , phosphorylated NF κ B p65 (p65-p), NF κ B p65 (p65), COX-2, and β -actin by immunobloting. E, F: THP-1 cells were serum-starved as in D. The cells were then treated with indicated concentrations of C16:0 for 24 h (E) or pretreated with indicated concentrations of DHA for 1 h and then coincubated with 150 µM C16:0 for 24 h (F). The resulting culture medium supernatants were assayed for IL-8 by ELISA. ** P < 0.01: significantly different from vehicle control (E) or from C16:0 alone (F).