Fig. 7.
Large rHDL, but not hHDL, attenuate TG secretion in ABCA1-silenced McA cells. A: Small (rHDLsm) and large (rHDLlg) recombinant HDL and human HDL were characterized for size by NDGGE (left) and electrophoretic mobility by agarose gel electrophoresis (right). Proteins were visualized by Coomassie Brilliant Blue G-250 staining. B: Control or ABCA1 siRNA transfected (25 nM for 48 h) McA cells were incubated with 10µg protein/ml of either lipid-free apoA-I (LF-AI), rHDL, or hHDL in the presence of [3H]oleate + 0.8 mM oleate for 12 h and the amount of newly synthesized TG secreted into the medium was quantified. C: Cellular protein from the experiment in B was harvested and ABCA1 and p-PI3K p85/p55 expression was examined by Western blot analysis. Western blot data for control siRNA rHDL incubations were similar to that for the lipid-free apoA-I incubation and are not shown. ** (P < 0.01), *** (P < 0.001); ns, not significant, by one-way ANOVA (Tukey's multiple comparison test).