Fig. 4.

Transfer of [¹³C]cholesterol from MβCD-treated [¹³C]cholesterol-loaded macrophages to adjacent SMCs. In this experiment, “accessible cholesterol” was removed from the plasma membrane of the [¹³C]cholesterol-loaded macrophages by incubating the cells with MβCD for 30 min. The macrophages were then washed extensively and plated onto a monolayer of [¹⁵N]choline-labeled SMCs (∼90 to 95% confluency). NanoSIMS images were recorded from the cell surface (Left) and the cell interior (Right). Note the negligible amounts of ¹⁵N enrichment in SMC nuclei. Mosaics of ¹³C/¹²C and ¹⁵N/¹⁴N NanoSIMS images (16 images, each 48 µm by 48 µm) show seven ¹³C-enriched macrophages (yellow arrows) on [¹⁵N]choline-enriched SMCs. A larger NanoSIMS mosaic containing this region is shown in SI Appendix, Figs. S7 and S8. Ratio scales were multiplied by 10,000. (Scale bars: 20 μm.)