Fig. 3: GRASP55 deficiency causes supersized LDs in intestinal epithelium.

a–c H&E and Oil Red O staining images of jejunal epithelia. Intestinal tissues were taken from 12-week-old Grasp55^+/+ and Grasp55^−/− mice that were fasted for 16 h (a) or 4 h after oral gavage of olive oil (b, 10 μl g⁻¹ of body weight). Quantification of stained lipid droplets (LDs) was performed by measuring sample absorbances at 510 nm (c, n = 7). The readings were normalized to the background value obtained from a non-induced fasting control. Scale bars: 50 μm. d Intestinal triglyceride (TG) contents were measured in jejunums of 12-week-old Grasp55^+/+ and Grasp55^−/− mice that were fasted for 16 or 4 h after olive oil bolus (olive oil, 10 μl g⁻¹ of body weight, n = 6). e Electron-microscopic (EM) images of mouse jejunum 4 h after oral gavage of olive oil (10 μl g⁻¹ of body weight). Arrows indicate cytosolic LDs. Quantitative analyses of LD diameters are summarized in (f) (Grasp55^+/+, n = 313 from five mice; Grasp55^−/−, n = 307 from five mice). Dashed circle represents the supersized LD (diameter, >5 μm). GRASP55 deficiency increased the LD size from 0.74 ± 0.02 μm to 3.19 ± 0.16 μm (p < 0.01). Scale bars: 5 μm. g, h EM images showing chylomicrons of mouse intestinal epithelial cells. Mouse jejunums were prepared 2 h after oral gavage of olive oil. Arrows indicate chylomicron particles. Quantitative analyses of chylomicrons are summarized in (h). The number of chylomicron particles in each EM field (3.72 × 3.72 μm) of the Golgi region was determined (n = 50 from five mice each). Scale bars: 500 nm (enlarged: 200 nm). Data are shown as mean ± SEM. n.s.: not significant, **p < 0.01. All p values were calculated by unpaired two-tailed Student’s t tests. Source data are provided as a Source Data file.