Astrocytes shed extracellular vesicles that contain fibroblast growth factor-2 and vascular endothelial growth factor.

We previously set a three-cell-type coculture system in which neurons and astrocytes synergistically induce brain capillary endothelial cells to form a monolayer with permeability properties resembling those of the physiological blood-brain barrier. Moreover, we recently found that neurons produce fibroblast growth factor-2 and vascular endothelial growth factor and secrete them at least in part by shedding extracellular vesicles. In this study, on the basis of immunofluorescence, scanner electron microscopy and Western blot analyses, we concluded that also astrocytes in culture shed extracellular vesicles that contain the same angiogenic factors, as well as beta1-integrin, a membrane protein that is considered a marker of shedding. Vesicles released by astrocytes are smaller than the ones produced by neurons and have an average size of 150-500 nm.