FIGURE 7.

TLR-induced TAG retention in human monocyte-derived macrophages. A, LPS induces human macrophages to retain LD. After incubation overnight in medium containing radiolabeled FA, the cells were washed and chased for 48 h in medium that contained LPS (10 ng/ml) or no LPS. LD were analyzed as described under “Experimental Procedures” and the legend to Fig. 1. Data averaged from three donors. Bars indicate mean + 1 S.D. B, relative increase in TAG retention in LPS-stimulated cells over time (unstimulated cells = 1). 10 ng/ml LPS was added after overnight FA loading. Mean ± 1 S.E. for three different donors, each studied in quadruplicate. C, FA-loaded macrophages were exposed to the indicated concentrations of LPS for 48 h. D, [³H]FA remaining in TAG 48 h after adding LPS (10 ng/ml), PAM (1 μg/ml), poly(I:C) (5 μg/ml). Fold increase above FA-loaded cells is shown (no stimulus). Mean + 1 S.D. of six experiments using macrophages from different donors, each with n = 4. E and F, uptake (E) and incorporation into TAG (F) of [¹⁴C]oleate by cells that were loaded with FA 48 h earlier and stimulated with LPS (or not) for 24 h prior to study. Data are from four donors, each with n = 4 determinations/time point. Bars indicate mean + 1 S.D. *, p < 0.05; **, p < 0.01.