Since functional GJIC required Cx43 expression, we performed immunoblot analyses of whole-cell extracts in co-cultures, 2 days after loading (Figure 5C). Strikingly, miR-5096 mimic down-regulated Cx43 expression in transfected U87, while it up-regulated Cx43 expression in HMEC. The immunofluorescent labelling of Cx43 in U87 further demonstrated the time-dependent decrease in heterocellular GJIC (see supplementary Figure S4). These results suggest that miR-5096 modulates Cx43 expression and GJIC, in a time- and cell type-dependent manner. In spite of the decrease in Cx43 expression, U87 loaded with miR-5096 mimic were still able to increase the formation of a capillary-like network at 5 hours (Figure 5D).