Fig. 3

Pattern of migrasome in vitro cultured RPE cells. A, B RPE cells were treated with TGF-β1. The expression of TSPAN4 was then analyzed by western blots and quantitative reverse transcription polymerase chain reaction (RT-qPCR). Qualified protein expressions are shown. C RPE cells were infected with TSPAN4-GFP lentivirus. Migrasomes and retract fibre (RF) were observed by confocal microscope. Scale bars, 25 μm. D TSPAN4-GFP RPE cells were transfected with scramble shRNA (sh-Scb) or TSPAN4-inhibiting shRNA (sh-TSPAN4). Cells were then visualized by confocal microscope. Scale bars, 10 μm. E Time-lapse photography of TSPAN4-GFP transfected RPE cell. Retract fiber extension, migrasome formation and degradation are shown chronologically. F The TSPAN4-GFP transfected RPE cells were seeded on a Transwell insert. After cultured for 48 h, the Transwell membrane was harvested and subjected to SEM. Migrasomes and retract fibers were marked by yellow arrowhead. G Magnified images were captured by SEM and TEM. Migrasomes were marked by yellow arrows