FIGURE 3.

Monensin similarly stimulates exosome release and prion transmission in neuronal cells. A, increasing concentrations of MON were tested for toxicity to GT1-7 cells, and no toxicity was observed at all concentrations tested. B, Western blotting analysis for the presence of PrP^Tot and PrP^Sc in control- and monensin-treated, prion-infected GT1-7 cell lysates and exosomes (Exo) released from prion-infected GT1-7 cells. The blot confirms that exosomes released from monensin-treated cells contain PrP^Sc. C, AChE assay of isolated exosomes indicating that MON also stimulates exosome release from GT1-7 cells. Cell blot analysis of recipient cells reveals increased levels of PrP^Sc and prion transmission following exposure to prion-infected GT1-7 donor cells in the presence of MON. D, AChE assay of isolated exosomes indicating that treatment with GW4869 decreases exosome release from GT1-7 cells. Cell blot analysis of recipient cells exposed to prion-infected GT1-7 cells in the presence of GW4869 reveals a corresponding decrease in PrP^Sc and prion transmission. Data are presented as mean ± S.E. (n = 3). **, p < 0.01; ***, p < 0.001. DMSO, dimethyl sulfoxide.