Maprotiline

All modulators were dissolved in dimethyl sulfoxide (DMSO), if not indicated otherwise. Dimethyl sulfoxide concentrations in the final solution never exceeded 0.14% at the highest test concentration of the respective modulator and were further reduced by serial dilution of the compounds. Pregnenolone sulfate, allyl isothiocyanate (AITC), CFA (containing 1 mg·mL⁻¹ of heat-killed and dried mycobacterium), diclofenac, maprotiline, primidone, and clotrimazole were purchased from Sigma-Aldrich (Deisenhofen, Germany). For behavioural studies, primidone was suspended in 0.5% Tween 20 (Sigma-Aldrich) which was also used as vehicle control.

To test the effects of other antidepressants on the infection of Vero cells with pp-VSV-SARS-CoV-2 spike or pp-VSV-G, we treated Vero cells for 4 h with 10 or 20 μM imipramine (Sigma-Aldrich; # I 0899), 10 or 20 μM desipramine (Sigma-Aldrich, # D 3900), 5 μM sertraline (Sigma-Aldrich; # S 6319), 10 or 20 μM escitalopram (Sigma-Aldrich; # E 4786), 10 or 20 μM maprotiline (Sigma-Aldrich; # M 9651) or 25 or 35 μM fluoxetine (Sigma-Aldrich; # 56296-78-7). Amitriptyline, desipramine and imipramine, were dissolved in 0.9% NaCl, all other antidepressants in DMSO with a final concentration of 0.1% DMSO. Controls were 0.9% NaCl or 0.1% DMSO. We then determined the activity of acid sphingomyelinase or infected the cells with pp-VSV-SARS-CoV-2 spike or pp-VSV-G particles for 24 h and then determined the expression of eGFP or the expression of ACE2 on the cell surface as measurements for infection as above.