Fig. 1.
ABCG1 has a critical role in nonhematopoietic cells. A: Schematic of BM transplantation studies. Wild-type and Abcg1−/− mice were irradiated and received BM from either wild-type or Abcg1−/− donor animals. After a 4 week recovery period, all mice were fed a HF/HC (21% fat, 0.2% cholesterol) diet for 16 weeks. B–E: Frozen lung sections (10 μM) of BM-transplanted mice [as in (A)] were stained with filipin for the presence of free cholesterol. White arrows mark filipin-positive areas. Images are at 20× magnification. F: Frozen lung sections (10 μM) from Abcg1EEC-KO mice (Abcg1−/− mice receiving Abcg1+/+ BM) were stained with antibodies for T2 cells (pro-SP-C; green arrows) and macrophages (Mac-3; red arrows), followed by staining with filipin (blue arrows) for free cholesterol. White arrows indicate areas of colocalization. Images are at 100× magnification. G–J: Representative electron micrographs (original magnification: 9,900×) from BM-transplanted mice [as in (A)]. K: The relative area of lamellar bodies within each T2 cell was determined in electron micrographs (n = 32) from each group of transplanted mice (G–J). Significance was measured by two-way ANOVA followed by Bonferroni correction. Data are expressed as mean ± SEM. *P < 0.01 wild-type versus Abcg1−/− donor; §P < 0.01 wild-type versus Abcg1−/− recipient. AM, alveolar macrophage; CC, cholesterol crystal; LB, lamellar body; LD, lipid droplet.