Visualization of Mechanical Force Regulation of Exosome Secretion Using High Time-Spatial Resolution Imaging.

Exosomes are small endosome-derived extracellular vesicles that participate in cell-cell communication, particularly in the context of tumorigenesis, and their secretion is influenced by the tumor microenvironment. While previous studies suggest that mechanical forces may enhance exosome release, the direct relationship between these forces and exosome secretion needs to be further characterized. Here, we utilized dual-color CD63 reporter-based high-speed live-cell imaging to visualize how mechanical forces influence exosome release in situ. Through live-cell tracking, we observed the dynamic fusion of multivesicular bodies (MVBs) with the plasma membrane (PM) to release exosomes at the single-vesicle level. More importantly, we directly detected a real-time stimulatory effect of mechanical forces on exosome release, with a bulk release of exosomes occurring under mechanical pressure stimulation. Furthermore, we identified mechanical force-induced actin rearrangement as a crucial determinant of exosome release. Our findings provide direct insights into the role of mechanical forces in exosome release and lay the groundwork for developing potential strategies to target disease-derived exosomes from their source.