Donor cells were loaded or not (E) with miR-mimic (M; 30 nM, hatched) or miR-inhibitor (I; 30 nM, white). The miR levels were determined by qPCR in donors (left) and acceptors (right), after 12 h of co-culture, and measured relative to U6 snRNA. Values are means ± SD of triplicate measurements from three experiments; *P<0.05 vs empty (Mann-Whitney U test and Kruskal-Wallis test; n = 3). A. Transfer of miR-145 from HMEC to U87. B. Abolition of miR-145 transfer to U87 when cells are co-cultured in transwell plates (non-contact). C. Transfer of miR-5096 from U87 to HMEC. D. Inhibition of miR-5096 transfer to HMEC by carbenoxolone (100 μM), a gap junction blocker. Note that carbenoxolone does not affect miR-5096 level in transfected U87.