Fig 3.

EBOV infection is reduced by the ASMase inhibitors imipramine and desipramine. (A) HeLa cells were pretreated for 1 h with the ASMase inhibitor imipramine (25 μM) prior to the addition of the GFP-expressing, replication-competent EBOV at an MOI of 0.4 (ZEBOV-GFP, upper panels). The cells were fixed, and their nuclei were stained with DAPI (lower panels). Cells were then visualized using an epifluorescence microscope. The cells infected in the presence of the indicated concentrations of imipramine (open circles) were counted, and dose-response curves were fitted to the data using GraphPad Prism software. As each drug is water soluble, medium alone was used as a control (solid circles). (B) To test if drug impacted infection similarly at a low MOI, cells were again challenged with virus in the presence of imipramine (open circles) but at an MOI of 0.05. Medium-alone control is shown as solid circles, and data were processed as for panel A. (C) Cells were treated with desipramine (open circles) or medium alone (filled circles) at an MOI of 0.3. Data were processed as in panel A. (A to C) Representative experiments are shown with each point in triplicate. The EC₅₀s for imipramine and desipramine were each calculated to be 3 to 5 μM and were the same for each MOI tested.