Figure 11. SR-BI deficiency decreases PPARα activity in macrophages.

(A) PPARα activity was measured using serial doses of nuclear extracts (NEs) from WT and Sr-b1^–/– macrophages treated with 100 μg/mL acetylated LDL and 5 μg/mL Sandoz 58035 (FC enriched) for 24 hours. The data are expressed as mean ± SEM from 3 independent experiments (n = 3 per group). *P < 0.05, **P < 0.01, ***P < 0.001 by unpaired Student’s t test. (B) WT and Sr-b1^–/– cells were FC enriched and treated with or without either CP-775146 or GW6471. The levels of PPARα, TFEB, and c-Jun in nuclear extracts were then detected by Western blotting. The blots are representative, and the numbers are the mean of 2 experiments, in which the values are normalized to either basal WT (green, regular font) or basal Sr-b1^–/– levels (red, italic font). (C) WT and Sr-b1^–/– macrophages treated with 10% FBS or enriched with FC by incubation with acetylated LDL and Sandoz 58035 for 24 hours. The expression of mRNA encoding PPARα was then measured by real-time PCR. (D) The expression levels of mRNA for TFEB, Beclin-1, Rab7, LC3, VPS34, and ATG5 were determined by real-time PCR in FC-enriched WT and Sr-b1^–/– macrophages treated with vehicle alone or with either CP-775146 or GW6471. (E) The relative PPARα mRNA levels were measured by real-time PCR in FC-enriched WT and Sr-b1^–/– macrophages treated with vehicle alone or with CP-775146 or GW6471. In C–E, the data are expressed as mean ± SEM from 3 independent experiments (n = 3 per group). *P < 0.05, **P < 0.01, ***P < 0.001 by 1-way ANOVA with Bonferroni’s post hoc test. NS, not significant. (F) The expression of Beclin-1, TFEB, VPS34, LC3I, LC3II, p62, Rab7, and GAPDH was analyzed by Western blotting in FC-enriched WT and Sr-b1^–/– macrophages treated with vehicle, CP-775146, or GW6471. The blots are representative, and the numbers are the mean of 2 independent experiments. In B and F, the values are normalized to either basal WT (green, regular font) or basal Sr-b1^–/– levels (red, italic font).