The data herein describe the discovery of in vitro anti-prion activity of a novel aromatic monocation. The anti-prion activity was demonstrated in two different cell Fenoldopam hydrochloride culture models, including a cell type that is relevant to natural prion disease. While the anti-prion effects described herein were discovered while using DB772 to eliminate BVDV from primary sheep microglial cells and Rov9 cells, to the authors�� knowledge there are no published reports of phenyl-furan-benzimidazole cations with anti-prion activity. In addition to the PrPSc inhibition, DB772 treatment also inhibited BVDV in both cell lines; however, it did not cure most of the cell replicates as BVDV antigen and BVDV RNA returned to detectable levels in one microglial replicate and in all of the Rov9 cell replicates. This incomplete pestivirus inhibition is different from what was demonstrated in primary bovine fibroblasts. The differing results may be due to differences in the strains of BVDV that were tested, as well as the different cell types. The cytotoxicity of DB772 was evaluated in sheep microglial cells and Rov9 cells. The 50% cytotoxicity point was similar between sheep microglial cells and Rov9 cells and is also similar to the previously demonstrated CC50 of 8.6 mM in B16 melanoma cells. These values are in contrast to previous cytotoxicity studies using DB772 in Madin-Darby bovine kidney cells, in which the CC50 was substantially FGIN-1-27 higher at 215 mM. The discrepancy between these CC50 values is possibly a reflection of the different cell types, but may also be a result of the different culture conditions used. Initial investigations into the mechanism of action were conducted and while no mechanism was identified, some potential mechanisms have been ruled out. Expression of PRNP is required for PrPSc permissiveness and the level of expression correlates with PrPSc permissiveness ; thus, one obvious mechanism of PrPSc inhibition would be the partial to complete inhibition of PRNP expression. There was no evidence that DB772 inhibited PRNP expression, as PRNP transcript levels and total PrP protein levels were not decreased. In fact at passage four, microgliaSc/DB772 and microgliaC/DB772 cells have significant increases in PRNP transcript and total PrP protein levels as compared to the untreated controls. This confirms that DB772 does not inhibit PrPC expression in microglial cells and suggests that PrPC expression may increase in response to DB772 exposure. While the levels of PrPC were increased, it is unclear if the increase is significant enough to be biologically relevant as the magnitude of change was small. Similarly, there was no evidence of PRNP expression inhibition in Rov9 cells as the direction of changes in PRNP transcript levels in Rov9 cells was towards an increase in PRNP transcript levels with DB772 treatment, and no change was identified in total PrP levels. The difference between the sheep microglial cells and Rov9 cells regarding PRNP transcript levels and total PrP levels is possibly attributed to the artificial PRNP expression system used in Rov9 cells, which is unlikely to respond to the same stimuli as the natural PRNP promoter. This highlights the importance of using a natural prion cell culture model when investigating the mechanism of action of anti-PrPSc compounds.