Fig. 2

Observation of migrasome formation and production from TGF-β1-treated retinal pigmented epithelium (RPE) cells. A A flow chart of ex vivo model preparation with rat RBCCs. B TEM and SEM of RPE in the normal control group. TEM shows the orderly structure of apical microvilli, basal infoldings (BI), and extracellular vesicles (EVs) are visualized at higher magnification on the right portion of the figure. SEM visualizes the apical side of RPE in normal control group. The white hexagonal outline is a single cell. The structure of extracellular vesicles is visualized at higher magnification in the boxed areas. C TEM and SEM of RPE in TGF-β1 treatment for 12 h. TEM shows RPE transformation and vesicles forming from microvilli and BI. SEM visualizes EVs formation at the apical side of RPE. The structure of extracellular vesicles is visualized at higher magnification in the boxed areas. D TEM and SEM of RPE in TGF-β1 treatment for 24 h. TEM shows the migrated RPE away from Bruch’s membrane (BM). SEM visualizes the transformation of RPE and releasing EVs at the apical side of RPE. The structure of extracellular vesicles is visualized at higher magnification in the boxed areas. E Confocal images of control and TGF-β1-treated RBCCs labeled with TSPAN4 (green). The integrated density of figures was measured by Image J and shown in chart. Scale bar, 50 μm. RBCCs, retinal pigment epithelium–Bruch’s membrane–choriocapillaris complex. TEM, transmission electron micrograph; SEM, scanning electron micrograph; BM, Bruch’s membrane; BI, basal infoldings