Figure 1. Low dose LPS reduces the expression and function of cholesterol transporters.

(A) WT BMDM cells were either treated with low dose LPS (50 pg/mL) for the indicated time periods or left untreated for 18 h, and the expression levels of Srb1, Abca1, and Abcg1 transcripts were measured by real-time RT-PCR assays and standardized against Gapdh levels. Each experiment was performed in triplicate. *, p < 0.05 compared with the untreated control samples. Error bars represent SD. (B) WT BMDM cells were either untreated or treated with low dose LPS (50 pg/mL) for 6 h and 18 h followed by Western blot analysis of total cell extracts (70 μg) using SRB1, ABCA1, and ABCG1-specific antibodies. Antibodies against GAPDH were used as the internal loading control. The data are representative of at least three independent experiments.(C) The BMDMs derived from WT mice were radiolabeled with [³H]cholesterol in cell culture medium for 18 h and then treated with or without low dose LPS (50 pg/mL) in the presence of apoA1 (10 μg/ml) or HDL (50 μg protein/ml). Cellular cholesterol efflux was analyzed in liquid scintillation counting assays, and the efflux rates were calculated as described in the supplemental methods. Efflux rates were expressed as means ± standard deviations from three independent experiments, each performed in triplicate. *, p < 0.05 compared with the untreated control samples.