Figure 4.

Exosomes mediate the microRNA (miRNA) communication between noncontacting MSCs and astrocytes mainly through the gap junction intercellular communication. Data show that cel-miR-67 is expressed in cel-miR-67 expression plasmid-transfected MSCs (A). Luciferase expression in the astrocytes was significantly increased after coculture with MSCs. The luciferase expression significantly decreased in astrocytes cocultured with cel-miR-67 expression plasmid-transfected MSCs compared with negative control cel-miR-239 expression plasmid-transfected MSCs. Fifty nanometer filter but not the 100 nm filter significantly inhibited the decrease of luciferase expression in astrocytes cocultured with cel-miR-67 expression plasmid-transfected MSCs. miRIDIAN miRNA inhibitor of cel-miR-67 counteracted the effect of cel-miR-67 on the decrease of luciferase expression in astrocytes. Furthermore, 150 μM carbenoxolone also substantially inhibited the downregulation of luciferase expression in astrocytes cocultured with cel-miR-67 expression plasmid-transfected MSCs (B). The cel-miR-67 was primarily located in exosome-enriched fractions with very low levels in the media (C).⁺, p < .01 compared with cel-miR-67 transfected medium group. *, p < .05 compared with the astrocytes cocultured with cel-miR-67 expression plasmid-transfected MSCs; ^#, p < .05, compared with the 100 nm filter applied.⁺, p < .01 compared with cel-miR-67 transfected medium group (n = 3 per group). Abbreviation: MSC, mesenchymal stromal cell.